Confused - Hydronic air handler VS heat pump VS heat pump plus furnance
Hey all,
I am in an area where we have big swings throughout the year - typically low double digits (occasional single) to high 90's. Nat gas is relatively cheap, with many new homes having radiant at least on the first floor.
- I was originally set on going with a two-system (ducted first and second) Daikin Fit or Mitsubishi HH heat pump system. Handler in attic and a pump; handler in basement and a pump. Of course, I need to think about heat strips. My understanding is that this approach provides comfortable normally humid air.If the heat strips come on, it will be akin to forced hot air.
- I then spoke with an installer that is doing closed-loop hydronic airhandler system. I would need a boiler, and then he would do two systems like I mentioned above, except it would be Aspen hydronic air handlers and Amana condensers. My understanding here (compared to traditional forced air) is that this approach provides comfortable, normally humid air.
- Searching around on the web, I ran into some posts regarding a "heat pump with furnace." I wasn't able to determine if this was a "duel fuel system" as it sounds similar, but I presume this is where the heat pump would handle cooling and moderate heating, and in the event the heat really needs to get cranked, the furnace would turn on. Is it correct that the "furnace" aspect of this system is essentially forced hot air, and would be much drier than 1 and 2 above?
Separately, my intent is to use gas if I can, and #2 sounds attractive. I know nothing about cost nor Aspen, but it sounds like a plausible way to approach things. I'd appreciate any guidance on that front.
Thanks!
Comments
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Do not call that person back. Neither a boiler nor furnace nor electric strips dry out your home’s air in this configuration. Your home’s air is dry in the winter because winter outside air is dry and is making its way inside. So no, a boiler attached to a hydronic coil will not keep the home more comfortable. That is snake oil!
Either a furnace or boiler can be attached to a ducted heat pump. Generally, a boiler is more expensive and more complex for the task, so isn’t usually chosen.
If your home is dry, seal the leaks. You can also add a humidifier. You’ll notice that during the summer, an air conditioner drains water OUT of the home. That actually removes humidity. A furnace/boiler/heat pump do not drain during the winter.
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Why are you looking at equipment? Is this a new build, reno or replacement? Also what are your local energy costs?
Double digit is not that cold for modern hyper heat units as most will deliver their nameplate rating even in single digit territory. Properly sized, you most likely won't even backup strip heaters.
I'm in a bit colder climate with cheap gas and hydro and heat pump works out to about wash in terms of operating costs. Not having gas saves about $350/year in meter fees which pays for one month of heat, so cheaper overall.
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During the winter a humidifier is needed to add moisture to the air. Installing a boiler for a hydronic air handling is going to be more expensive if you currently do not have a hydronic system in your home vs a furnace or heat pump.
There are some newer products in the market that are essentially hydronic furnaces. They modulate the water temps to control discharge air temp of the unit providing a more consistent air temp while the unit is running, unlike a gas furnace that may at best have low / high fire or just a single stage gas valve. This approach obviously works, but you do feel the air stratification when the unit cycles. Navien has an interesting product out with their "water furnace". I've seen them at the supply house but have yet to come across one on a service call. NTI has the GF150 which is similar, but has the capability to do domestic hot water and up to 50k BTU for radiant heat in one unit. IFlow HVAC has a very nice hydronic air handler as well with options for some zoning features. Viessman was supposed to have their version of this for the US market, but it was pushed back. The Aspen unit you were referring to is very basic on/off hydronic air handling unit.
If you plan on doing infloor radiant then I would say look into the boiler, hydronic air handler combination otherwise it might not be a cost effective solution. I'm actually looking into something like this for my own home, mainly because I want infloor radiant on the first floor and we are looking at putting an sunroom type addition on where infloor would work much better than reconfiguring my existing ductwork.
Owner of Grunaire Climate Solutions. Check us out under the locate a contractor section. Located in Detroit area.
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Reno with addition. Generally speaking it's either a wash or gas comes out as cheaper to run for heat compared to heat pump.
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Why is there so much conflicting information? I regulary see that a hydronic system is always going to be superior to a forced-air furnace as it is more "comfortable" due to humidity retention. Further, isn't this why steam is arguably the most comfortable?
It appears what I am referencing is wrong - but rather the "comfort" is due to the "radiance" of the heat versus the blowing air - is that correct?
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@Toasted when hydronic heat is described as “more comfortable” it’s not in the configuration you’re describing (which is forced water AND forced air). It’s usually in reference to forced water only - like radiators, radiant flooring, radiant ceiling, etc or steam. A hydro air handler IS forced air - think of it as a furnace with a bunch of expensive, unnecessary parts.
However, neither flavor system “retains humidity”. That’s not a heating system function. Install a humidifier and air seal to accomplish that. A boiler will not make your home more humid (unless it’s broken and leaking out).
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Houses get dry in the winter because air contains much less moisture when it's cold, and inside air leaking out and being replaced by outside air means the house loses humidity. All other things being equal, a house with forced air will lose more air to leakage than one with hydronic heat, because the forced air requires that parts of the house be pressurized and other parts depressurized in order for the air to flow.
The tighter the house is the less of a factor this is. If you are putting on an addition and building it to modern standards — actually following the letter of the current IRC and IEEC — this should be a non-issue. Building to modern standards addresses many of the comfort issues with heating, a lot of the conventional wisdom dates from a time when houses were much leakier and more poorly insulated.
Tight, well-insulated houses are just more comfortable. I like to say an ounce of insulation is worth a pound of hydronics.
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Is it a gut reno?
If yes, then seriously consider sealing and insulating the heck out of the house, and then go with the best heating\cooling setup you can afford.
Does the house have existing ductwork?
Swinging hammers and fitting pipe…bringing the dream to life
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There are a lot of persistent myths out there. The one "I regularly see that a hydronic system is always going to be superior to a forced-air furnace as it is more…" is a common one.
When it comes to heat, BTU is BTU. Doesn't matter how it is delivered and if properly designed, there is no comfort difference. A heating system can't dehumidify, so there is no way for it to dry a place out. Sometimes air handlers mounted in unconditioned space like an attic can significantly increase air leaks, which as pointed to above, will dry the house out. The solution there is not hydronics, but fixing the bad install, which is simple, KEEP ALL EQUIPMENT and DUCTS INSIDE CONDITIONED SPACE.
Where lot of forced air systems have comfort issues, especially in older leaky structures, is they are way oversized (usually around me it is 2x to 3x). This means short bursts of hot air followed by long waits between calls as the house cools down. Once you have a reasonably well sealed/insulated structure with right sized equipment (even better modulating heat pump), this is a non-issue.
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Interesting Query:
The information that is often given has to do with the way that a person perceives what is happening as opposed to the science of what is actually happening.
To fully understand the concept you need to study how humidity actually works.
This is a Psychrometric chart:
If you look at the Enthalpy line that I have marked in Red you will see that what we consider as comfortable ends up at about 70° with 50% Relative Humidity (RH)
You can see that you will also feel just as comfortable with a temperature above 90° as long as the RH is lower than 20%. Likewise a 60° air temperature at a RH above 90% will also feel about the same. It all has to do with the human body air conditioning system, perspiration. The dryer the air is the faster your perspiration evaporates off your body. That evaporation cools you down. When it is hot and humid the air can not evaporate your perspiration as fast so you feel the heat. If the humidity is low and it is cold, you feel the cold even more because the perspiration is evaporating much faster.
Now lets take a look at the nuts and bolts these numbers are by no means accurate but used to explain the concept
As air temperature increases, one pound of air takes up more space then that pound of air at a lower temperature. Also, the amount of water vapor that is in the air does not change, however the water vapor wants to be equal and balanced in the larger space that the pound of air occupies. So the percentage of humidity in any given cubic foot of space will change with the temperature.
That is a difficult concept to grasp so to make it simple let's say that one pound of air occupies 13.5 cubic feet of space at 70° (at atmospheric pressure of 14.7 PSI absolute or 0.0 PSI gauge)
Let’s say that the relative humidity of that air is 50%
So to make it simple to see in your mind's eye. We will use a gallon of water in a bucket to represent the air, and Red dye to represent the humidity. By increasing the temperature of the air (the water) the air takes up the space of 2 gallons but the amount of humidity (the red dye) is still the same so the water looks like it is pink (less concentrated red)
Now lets lower the air temperature so it takes up less space. For example 1 pound of air will now only occupy ½ gallon of space. It is still the same 1 pound of air but it will take up less space. The humidity is also the same as it was before so the humidity will only need to fill up ½ gallon of space. This will make the relative humidity a higher percentage (the Red dye will appear darker) because there is less space for the water vapor in the air to occupy.
Now that is the “science for dummies” behind the relative humidity numbers. But in the real world the room that the air is located in does not expand and contract to fit one pound of air. So what happens to the rest of the air in the room when the colder temperature room is heated? That air leaves through the doors and windows and cracks in the plaster and the light switch covers and the floor moldings and any other place that “Infiltration” can happen. And when that air leaves, it takes some of that humidity with it.
Likewise as the temperature drops in the room, then the air from outside the home will “infiltrate” back into the room because there must be the same volume of air regardless of the temperature. Of course, the room is as big as the room is, and does not change size based on the room temperature. So that means that as the temperature drops and the amount of air by weight shrinks. Outside air that is colder will enter the room by infiltration to make up that void. That outside air has a certain amount of humidity in it. And that air is much colder in the winter. If that is 50% relative humidity air at 20° then when that air is heated up to 70° the relative humidity will be much lower as that colder air expands from 20° to 70°
You might want to read that part again. as the temperature drops and the amount of air by weight shrinks. Outside air that is colder will enter the room by infiltration to make up that void. That outside air has a certain amount of humidity in it. And that air is much colder in the winter. If that is 50% relative humidity air at 20° then when that air is heated up to 70° the relative humidity will be much lower as that colder air expands from 20° to 70°
So you are taking 50% relative humidity (RH) air and heating it from 20° to 70° which makes it about 20% Relative humidity air to replace the heated air that was 40% RH but migrated outside during the infiltration process. Eventually you will have a very low relative humidity in the home.
How Does it Feel?
With that understanding of Relative Humidity and what the temperature does to the RH, you can now compare the different types of heating systems and see how they make you feel.
Gas or Oil furnaces will heat the air from 60° to as high as 160° (or more if poorly designed) and that will really dry out the relative humidity. As that very dry air leaks out of the duct work on the way to the rooms, the cooler basement, attic or crawl space air will suck more humidity from that air thru that leaking ductwork. But eventually that hot air will mix with the room air and the net result will be that the RH will get back to the rest of the air in the rooms. The net result from infiltration will be a dryer air will be blowing out of the duct work on your body. So your perspiration will evaporate faster to cool you off. So that feels dryer
The heat pump will blow 110° to 120° air on your body.The RH will be somewhat higher than the Hot Air furnace air but you will still feed chilled as a result of the cooler air blowing on you with a lower than the recommended 50% RH. So that feels cooler
A hydronic duct coil will offer you the same result but it will fall in between the very hot and the somewhat cooler air by providing a 140° air blowing from the ductwork. Many find this form of warm air heating the most comfortable.
As far as a radiator standing over next to the window, they depend on convection currents to move the heat from the water in the cast iron to the room. That air moves very slowly and is almost unnoticeable, and therefore the most comfortable. That makes you feel warmer and less dryer. Baseboard radiators have a similar result of low air movement.
Radiant floor heat has almost no convection heating. Radiant heating uses a different concept than air movement or convection. It is radiant heat like the sun. And we all know that the sunny places are much warmer than the shady places. You can feel more comfortable at a lower thermostat setting.
Bottom line: the relative Humidity in your home will always be lower in the winter and you should see what steps to take to get the RH at a comfortable lever. Just be careful as you can add too much humidity and that can cause other problems.
30% to 40% RH inside is more than enough in the winter
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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and how does it retain RH?
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Radiant floor heat has almost no convection heating. Radiant heating uses a different concept than air movement or convection. It is radiant heat like the sun. And we all know that the sunny places are much warmer than the shady places. You can feel more comfortable at a lower thermostat setting.
Comfort at lower ambient temperatures has always been a sales feature of radiant surfaces to heat a structure.
Comfort for me is also about noise, radiant wins hands down on that. Maybe a perfectly installed VS forced air system is 100% noise free, most aren't
Robert Bean has had it right for years IAQ is the key to absolute comfort, it is not just warming the space. Moving air moves dust, smells, everything else in the "air" space. Add or subtract moisture, filter, bring in some outdoor air if needed, etc.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream1 -
@EdTheHeaterMan That is a lot of information there which not easaly digestible. TLRD, the amount of moisture in the air that enters a fruance does not change, the only thing that happens is the air is heated. Once that hot air makes it back into the living space it mixes with the air there and the RH will be exactly the same as what it started with.
I would disagree that 120F air is cold. You definitely don't want 90f, but anything above 105F is considered warm by most people. It is also bad design to blow any air (hot or cold) at people directly, registers should always be place in a way to avoid this. This is not hard.
Also for comfort, short burst of 160F is much worse than nice steady flow of 110F air.
@hot_rod Having lived with radiant heating for a long time, I can tell you the thermostat settings don't change. People prefer a house that is between 70F to 75F, not much will change that. There is also zero air filtering with radiant, so you get the opposite of what most people think, which is a lot more dust.
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20C was plenty when I lived in the past 4 homes with radiant floors
For the past 4 years in a FA home I need the stat at 72 to stay out from under the Snuggly. Im sure it varies from person to person, that has been my experience.
And the Wirsbo sales spiel that helped sell millions of radiant systems🫢
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
The only things that effects humidity in the winter is outdoor humidity & temp, indoor temp and to a lesser degree how the house is sealed. The type of heating system has no bearing.
Virtually impossible for sealing to make much difference as humidity inside will constantly balance to the outdoor condition. Door get opened, infiltration and humidity travels almost instantly due to vapor pressure.
Only for laboratories museums and manufacturing is humidity usually controlled because it is expensive to do
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@Kaos said: "That is a lot of information there which not easaly digestible. TLRD, the amount of moisture in the air that enters a fruance does not change, the only thing that happens is the air is heated. Once that hot air makes it back into the living space it mixes with the air there and the RH will be exactly the same as what it started with."
I'm not so sure that you understood what I was trying to say. The air does expand at the higher temperature and the RH % of that hotter air will be lower by volume as a result. So the RH of the air in the duct work is much lower and the air in the room connected to the end of that duct. The lower % RH air will eventually balance to the original RH as the temperature in the room drops to the pre call for heat temperature. The post call for heat temperature will be warmer and that RH will be a lower % as a result, even if there were no air changes from outside air
Now lets take 20° outside air with a RH of say 40%. When there is an air change inside the home of say 1 per hour, then you have removed all the 70° air that was in the home and replaced it with 20° air at 40% RH, what happens to that RH when the 20° air is conditioned thru that furnace or heat pump or radiator? The 20° air will become 70°. And what will the RH of that 70° air be after it was 40% at 20°? If I understand the science correctly, the RH of that new air at 70° might be as low as 15%. So the hotter you keep your home, the more humidity you need to add. The looser the construction is, the more humidity you need to add. The tighter the construction is (less air changes per hour) will keep the moisture in the home longer.
That is the science as I was taught and understand it. And this explanation was to answer the conflicting info about hot air being dryer and heat pumps being less dry and Hydronic somehow being the least dry of heating systems. (so I think we agree on that) and why there is a lot of conflicting opinions about different heaters. Not a lot of professionals in our trade understand RH, enthalpy and the like. Some actually think that the water in the pipes somehow humidifies the air in the rooms.
It has nothing to do with the type of heater. It all has to do with air changes and the way Relative Humidity works. Some homes with Hydronic heat need less added humidity as a result of the better construction. Not because there is water going through the pipes that is somehow humidifying the home. That is just Balderdash! But if a Pro tells you something, then you must believe it because they get paid to know it. I think that is how it works.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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There are homes out there that have one air change per hour from air leakage but those are pretty old and drafty enough that most home owners would fix it. Most code min new construction is around 0.15 air changes per hour from infiltration, during that time people breath, cook, water plants and bathe. That adds a fair bit of moisture to the air so most code min homes are not that dry. Very tight houses need dehumidification (done by venting with an ERV or HRV) in the winter time because of this.
Regardless, the air handler and how hot it is has nothing to do with the humidity in the house. Most thermostats have around 2F deadband, so a 70F 40%RH house will go to 72F 37%RH at the end of the heat call (ie temperature changes but dewpoint does not). Doesn't matter what the source of the heat is or how hot the supply air is, this won't change. If anything a modulating unit can maintain a sub 1F setpoint, so house air temperature, thus relative humidity, will barely change.
When it comes to heating the RH of the air inside the air handler is irrelevant and I think it mostly confuses the situation. What we care about is the air we breath. So unless you stick your head over the register, you are breathing house air, no matter your heat source, that won't change.
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Not that hard to build a sub 1ACH@50PA house (about 0.05 air changes per hour from leakage). Those are tight enough that need some way to dry in the wintertime to avoid high humidity.
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Responding to several comments:
@ILikeEmOlder Reno and addition, all new ductwork. My objective is just that - to determine the best set up :)
@pecmsg Not sure if your question about how it retains RH was rhetorical? Either way, the discourse here helped me come to what I believe is the correct conclusion, (more below).
@Kaos I agree on the point regarding filtering, as I considered radiant floor and won't be going in that direction.
@Kaos and @EdTheHeaterMan Thank you both - I have also done research and believe you are both ending up in the same place which answers my question, leading me to the following:
We all know - including myself - that hydronic systems don't "add" any humidity through osmosis or other magical ways. 😁
It starts with psychrometrics per @EdTheHeaterMan, while the amount of water molecules isn't being reduced, the LH does drop due to them staying constant while the overall temperature of the air increases. I believe @Kaos touches upon this next point, but doesn't the aforementioned become an issue only if the house is "loose" as there becomes an actual deficit? In my case I am going to be insulating and sealing as best I can.
So now this leads me back to the question of what direction to go. A heat pump plus furnace is starting to make even more sense.
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I think heat pump + furnace is likely the answer for 95% of Americans. You included!
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And if I do a Daikin, that's going to be modulating. Question is, what's the savings if I just get a high quality full modulating furnace plus condenser? If I go heat pump, I likely won't really need duel fuel.
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Toasted,
Based on what has been said to this point…
- You can achieve a very high-performing envelope for the existing structure and the addition — this is a huge win.
- Your high-performing envelope is one that will sip energy, and therefore the energy source for heating is far less important.
- Maintaining year-round comfort at low operating costs is almost guaranteed if you find the right contractor to help you realize the plan you are currently putting together.
As far as the design of the existing structure and the addiiton is concerned, you really want to keep all the ductwork within conditioned space. Next, you want to have the two structures tie into each other in such a way where routing the ductwork of the two separate systems can be done most efficiently and effectively.
It looks to me like you are well on your way to creating a house where your original plan for heating and cooling the house with two separate ducted heat pumps is the best one.
Swinging hammers and fitting pipe…bringing the dream to life
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You don’t need dual fuel. Heat pump only is fine and saves on gas fees
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Thanks for your reply - the thing is, the addition is going to be on a crawl space, and I don't want to run a register and supply there to mix in with the first floor air. I planned on putting the handler in the basement, which isn't heated/conditioned. That said, you mention the importance of ensuring the ductwork is in conditioned space. Does this mean I need to now ensure I seal the crawl space and separately run mini splits in both the basement and crawl space?
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There's a lot of conflicting info simply because many if not most do not understand how things work.
My 150+ year old house with steam heat typically runs around 25% RH in the winter, and that's with a humidifier dumping 6+ gallons of water into the air a day. Without that humidifier it really gets dry.
My dad's 2006 house with forced air runs around 35% RH without any humidifier at all and it's generally 10 degrees colder where he is. My house is very drafty and his isn't. It's that simple really.Drafts cause low humidity in the winter, nothing else. It's not a mystery. Exhaust fans, bathroom fans etc also contribute towards this but most would rather lowering the humidity a little over smelling bathroom stink. You have to pick your battles.
A properly designed forced air system in a well insulated and sealed house with wood flooring up on a foundation is perfectly comfortable. If a house is drafty it'll generally be more comfortable with a radiant style system. Slab floors will be nicer if they're heated as well. It's best to look at a heating and cooling system as being part of the house, rather than separate. The entire thing is a "system". If you install a forced air system no matter how well designed into a drafty house on a cold slab you're going to feel cold all of the time and there's no gimmicks to fix it. Insulate the floor and seal up the drafts and it'll be comfortable.
Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.
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The more I am evaluating this the more I am thinking about KISSing the approach - keep it simple stupid.
I was originally enamored by the heat pump systems as I thought they were going to retain humidity better than other approaches specifically forced air furnace. Then I went to hydronic air handler as an alternative as I thought that would retain humidity better.
This all said, if I can avoid the downside of dealing with highly technical equipment where I am beholden to the installer for every single thing, and given gas is cost effective by me - doesn't it make sense to just go with a high end condensing unit (Amana?) and a fully modulating furnace for heat? If I am all sealed up I presume I won't be needed to blast the furnace.
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If you’re using AC, a heat pump is a no brainer. Add a furnace to it if you like. We can abandon the boiler idea here.
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This is where things can get complicated, especially with the majority of contractors simply not well versed on the “house as a system” approach.
A sealed crawlspace is superior to a ventilated crawl. Additionally, an unconditioned crawl space is a bad idea. Stale air in your crawl almost always leads to indoor air quality issues. Ventilated crawl spaces are rarely done well.
The cost difference between a basement and a crawl is often very little (especially in the greater picture).If you are committed to a crawl then make sure it has ample headroom and access.
For your proposed project, I would have the air handler that you plan to locate in the basement of the original structure serving the 1-story addition, with the trunk extended into the crawl. This is the simplest and most cost effective approach. Air handler is located “centrally” in the basement.
Swinging hammers and fitting pipe…bringing the dream to life
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"Does this mean I need to now ensure I seal the crawl space and separately run mini splits in both the basement and crawl space?"
No you do not need to condition the basement or the crawlspace. That is going to happen partially anyway. Just for example, I did a Central Air Conditioner for a customer In Brigantine NJ after Hurricane Sandy. FEMA dollars allowed them to lift their home from the ground so that the crawl space went from 2.5 ft off the ground to over 8 feet off the ground. As a result, they ended up with a very convenient place to install ductwork. It was still considered a crawl space as there was a dirt floor. After that work was completed they wanted to have the Central Air installed in the attic, just like everyone else does. This means that the new ductwork would be located in the attic and it would be operating when the attic could reach temperatures exceeding 115° in the midday with the sun beating on that roof. So I offered them a 3.5 ton cooling system but I also offered them a 3 ton system where the indoor unit would be located in the 8ft+ tall crawl space. The reduction in size was a result of installing the ductwork in a much more friendly temperature location. Two things happened with this option. The cost of the installation was about 8% lower, but more importantly, the operating cost was also reduced for as long as they owned that home. A 6,000 BTU Smaller compressor will use less electricity for as long as that compressor is operational.
Eventually they upgraded to a Gas Furnace in the Crawlspace. That added a small amount of heat to the space under the home. That heat that warmed the space under the home was not a perceived loss as their floors were warmer in the winter which made for an overall higher level of comfort in their home. So selecting the ductwork location for your heat pump is an important decision. Don't just do the easiest thing and put the second floor ductwork in the attic. See if you can install it within the envelope of your conditioned space and add soffits to cover them. That is a better design, although it may not look the best.
Why none of my competitors didn't offer them the lower duct work job still makes me wonder.
Hope this answers your query.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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Did you install a furnace and ductwork in a location that could still flood?
If the house was raised 8', I would assume that was decided to get it above the highest expected flood level, no?
Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.
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The cost difference between a basement and a crawl is often very little (especially in the greater picture).
I was very happily surprised to learn this very thing as I was getting quotes for an addition. We all can use more basement space!
NJ Steam Homeowner.
Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
See my sight glass boiler videos: https://bit.ly/3sZW1el1 -
Good Point…. Negative on the equipment getting flooded. The code official would not approve the permit if I did that.
The reason the house was raised so high… there was a laundry room on a slab on grade that was 5 steps lower than the first floor. That laundry room was completely flooded and everything in that room was a total loss. The main floor had only a foot or two of water damage. Since the laundry room was considered the base of the home and it was about 4 ft lower, that laundry room needed to be raised about. 6 foot. That left the rest of the main house a few feet higher with at least 3.5 feet of useable space for that furnace and duct work.
I didn't just fall off the turnip truck!
It took 6 more years before that happenedI
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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I mean, crawl space is typically ~3-4 feet. A comfortable basement height is at least 8 feet, and if you are using drop beams you probably want to be at least 9 feet to account for ductwork. So if we're talking CMUs, we're talking double the block, double labor, double the mortar, and a more structurally sound slab. Don't forget to french trench which likely wont be much more if any, since the perimeter is remaining static. Double the excavation and soil removal cost.
I was actually contemplating going full basement, so please say more around how the basement came out as slightly more versus the crawl space - unless you were getting crazy pricing for a crawl space which was more reasonable for a full basement.
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Very helpful, thanks.
What are your thoughts on 2-stage versys fully modulating furnaces?0 -
For the most part 2 stage and modulating furnaces are similar in price when equipped with the ECM variable speed blower motors. The communicating thermostats will make them work the best. Match that with a variable speed compressor on the outdoor unit and you will have a very quiet comfortable system (if your duct designer is knowledgeable). I was going to do that with an American Standard condensing unit in my old home in Brigantine NJ but was disabled before I got to it. (At least I got the radiant floor heating done)
The problem with all that technology is the cost of repairs. The warranty can be extended to 10 or 12 years by some manufacturers but that does not include the labor. And the apprentice will not be able to fix your system when there is a problem. You will always need the senior technician to work on that stuff. And when that guy leaves the company the next senior tech may not know your system as well as the old-timer that just left did.
If you are tech savvy and can handle the nuts and bolts of that more complicated equipment, then go for it. If you are going to depend on paying for every service call that happens, then I would try for something less complicated. The 2 stage is less technical and PSC blower motors use circuit boards that are less expensive.
Make sure you register the warranty online with what ever new equipment you decide to purchase. That will extend the manufacturer's parts warranty.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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yeah that’s why I was surprised. My GC said by the time you have to put down the support footings and extra structure for a crawl space it’s not much more for a basement. So get it quoted and see.
I assume it’s different if there’s bedrock
NJ Steam Homeowner.
Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
See my sight glass boiler videos: https://bit.ly/3sZW1el1 -
Thanks, definitely going to bid it out and see.
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@ethicalpaul Very interesting - it's not that much more. The biggest move in cost, surprisingly enough, is soil disposal.
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Regarding equipment, do I have this right?
- Heat pump: Electric Heat Pump, Electric air handler.
- Dual fuel heat pump: Electric and gas heat pump, air handler
- Furnace heating and AC: Furnace, air handler, condenser.
If so, now it's deciding between duel fuel or furnace.
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good enough!
Ask for a heat pump + furnace or furnace + AC. The pros will take it from there.1
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