Need Opinions For New Construction, Hydro Air vs. Hot Air in CT

Sarwat Patel

For a new construction, choices are a hydro air system or a hot air system.
Fuel used is LP

The house is about 6000 sq ft. Have spoken to three HVAC contractors. Initially the HVAC was specified as follows:

Hydro air, 9 sec oil fired boiler, 80 G indirect water heater, 2 variable speed air handlers, 2 Seer 13 A/C units. There are to be 5 zones(I understand these are not truly separated zones) 2 zones will be serviced by the air handler located in the attic. The three zones in the first floor would be serviced by the air handler in the basement.

I am going to be using propane for a lot of other functions, multiple fireplaces, multiple cooktops, dryer, etc. So if I use it for heating my rate (which does go up and down)would be 88c/Gallon. Anyway I have been always inclined towards using gas/Lp.

The HVAC contractor suggested that in case of using LP, using a hot air furnace system would be a good option as well. If we choose hort air, the boiler would be eliminated and we would use 2 two-stage 92% efficient hot air furnace. One would be located in the basement and one in attic. I have been advised against putting one in the attic.

Now I have always heard that hydro air is better than hot air. Since its all new construction, we have a clean slate to work with.

What do you suggest : Hydro air or Hot air, given that we are not dealing with an existing system. What would be the best choice.

Floyd

Just did a hydro air system...

went with downflo airhandlers and spiral ductwork.... the house used trusses instead of floor joists so I had plenty of room.
Sounds to me like you may want to consider more than two air handlers and go with smaller ones, depending on how the house is laid out....
Also may want to mix in a bit of radiant.... it can be done....
Would go with oil... didn't do the math but I think that at .88 you still would be better off with oil at .95 which is the going rate around her right now.
even if you go LP stick with the hydro and get a good high eff. boiler oyu will be much happier!!!
Make sure you get outdoor reset on the boiler and stick with the indirect also.
May even want to consider two smaller boilers rather than that big 9 section, which sounds like a bit of over kill, even for 6,000 sq. ft.

Bob Bona_4

if

given the choice, hydro-air. With a boiler, there are so many options, and no worries about heat exchanger cracking/leakage. Better efficiency using an indirect, and only one appliance (boiler) to lose heat through venting. I'm from CT also, and LP is not the fuel of choice in this area anyway, and it will be more costly to run per therm then any other fuel-plus the hazard factor is up there. Floyd is right about using radiant where you can, and I also have questions about using a 9 section boiler..has a heat loss calculation been done? That is awfully big for 6000 sq ft. Where are you in CT?

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keith

Hot Water

is the way to go. Gives you options that hot air can't.
installed hydro in my own house when I built it. Now that the dust has settled a zone of staple up radiant in my foyer is still possible. Towl warmers, pool heat exchangers,outdoor reset, a more comfortable humidity level in the house are a couple of things that come to mind. It sounds like the boiler is being sized for something else besides the heating application. possibly a pool heat exchanger or a huge demand for domestic hot water. If not then an accurate heat loss will probably push you to a 6 section boiler. The out put from the 6 section still gives you about 300 + - gallons of hot water per hour. I would also stick with oil as my fuel. More competitive pricing and you dont have to deal with looking at a tank sitting outside or even worse burying it in the groung. Not to mention the safety factor, fuel oil is a much more stable fuel. By the way which air handlers are you looking at? Good Luck with the new house.

kevin

Ditto....

You already have 3 very qualified people giving you very good information and reasons for hydro air, oil not LP. 93K btu/gallon vs.oil 140K per gallon. Definately check that heat loss again...good luck kpc

Paul Pollets

Why Hydro?

A boiler is a far better choice to power a coil in an air handler. I presume you wanted radiant floor heat in the home? I realise you need A/C but if I designed the home, it would use radiant floors, an oil-fired Viessmann boiler (propane is the most expensive fuel)and 92g V300 tank. I'd either use Unico HV A/C with HW coils (if required) or conventional air handlers, if duct sizing wasn't an issue. Hydro air is hot air, BTW. The source is simply a water heater...which won't last anywhere near the life expectancy of a German boiler. I'd speak to a radiant contractor who was experienced in A/C, You'd probably get a better system than the one you've detailed.

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JIM F.

I AGREE!!

we do a lot of work in greenich/stamford area. i do ALOT of hydro air. i agree with all the info on the posts above. i would suggst usung 2 boilers instead of one, and slightly oversized for the purpose any additions like radiant floor heat,basement remodel,want to heat your garage, etc. also if one boiler goes down in the middle of winter at least you have a back up heat source. not 100% but enogh to take the edge off. as to fuel type in my opinion oil would be the way to go, but can be done either way.
good luck
jim f. milford, ct.

ChrisL

Outdoor Reset not needed

One additional point- if you are only running hydro air, and an indirect for dhw, I would forgo the outdoor reset for boiler temp. You don't gain much from outdoor reset with hydro air.

Chris L

Sarwat Patel

Wow

Thanks. I was amazed at how many of you responded. I really appreciate it. So I guess hydro air is the way to go, but most of you mentioned that oil is the best fuel. LP does not gives the same result in combustion, also some of you mentioned hazard issues.

Can you expand on that.

See, I will have to get an underground tank anyway for LP, as I love gas cooking and have three LP fireplaces. PLus some other usages such as two grills and dryer etc. Since I would get the tank and deal with all that anyway, all I would have to to is upgrade the size.

I do realize that it does not burn as efficiently, however it buurns a lot cleaner, so I thought that at teh cost of paying a little bit more, it would be a cleaner system (also for the environment)

Given teh fact that I would have to do the propane anyway, I wanted to deal with one fuel (deliveries, bills etc) and I guess I am using the clean burn, as a factor to justify the lower performance.

I also did not follow the comment about outdoor reset.

Another thing that I was concerned about was that there are five bath exhaust fans, plus there will be a strong hood. I iwll be finding out specs on the cfm this week, so I was really concerned about the compensating for the air to ensure that there is no negative pressure. What should be some of teh steps taken.

Lastly, many places ideally I have read that the air handlers etc, shoudl not be in unconditioned space. However over 90% of homes have these in the attic. I have also heard negative comments about powered attic fans. But if a handler is placed in te attic, don't we need the fans to ensure the temperature doesn't get too high. I have a significant length of ridge vent. I don't remeber now, but I had followed the guideline of code and I think we had more. But we installed two fans of 1200cfm, thermostatically controlled. I may go for a kill switch on these if at a later date we find that they contribute to depressurizing.

I was glad to see some of you from Ct. I will send you individual e-mails as I am in Milford, CT and building in orange.

Thanks a bunch. Your responses were awsome

Sarwat Patel

size of boiler

Forgot to mention. In addition to normal heating we may have upto 1000-1500 sq ft of radiant heating (if and when we can afford it). Also there will be approximately 2000+ sq. ft in the basement that may be finished later that may be added as a zone later. I guess that's why the 9 sec boiler. However one of the contractors had designed two 4 sec boilers vs one 9 sec, which makes more sense according to all of you. But it was a few thousand more in te amount. Not something I have counted out simply due to the price. So even if its costs a little more to go wiht 2 small, is it worth it? Between burnham, well mclain and lennox, which would you recommend. The air handler were specs as lennox variable speed or trane variable speed.
Also one contractor spec 18 SEER A/C units. This bumped the price up by a few thousand as well. Between the two boiler vs one, and 2 18 SEER trane vs 2 13SEER lennox, the price diffrence was about 5G. Does that sound right. Also is 18 SEER worth the price diffrence. It has two stage (two compressors)

Cosmo

I am glad you are inquisitive, but remember this....

All the high efficiency equipment in the world cannot, and will never, replace a reputable contractor who properly installs the equipment. Many times I have seen expensive, condensing boilers installed with every single optional accessory available....installed w/ primary/secondary method near boiler piping. The only way a condensing boiler can run efficiently is when the return water is much cooler than the supply water, this means that you are sending all the heat where you want it- not back to the boiler to be recycled. The reason for primary/ secondary piping is to ensure that non-condensing boilers are not recieving cool return water which in turn never allows the boiler to heat up and run efficiently. You see, things have to be done right. A properly set-up oil-fired burner wether in a condensing boiler like the Viessman, or in any other well manufactured boiler will run very clean. With annual cleaning and combustion analysis it will always burn clean. It is said that oil is safer because #2 fuel oil's flash point is over 600 degrees, it must be atomized to burn easily. You can put some #2 fuel oil in a cup, throw in a lit match and nothing will happen (do not try this at home!). Propane however is highly flammable, and it is stored under pressure. A leaking tank, pipe, fitting can be very dangerous.... but as long as (here we go again) you have a good technician, there is nothing to worry about.

If you can afford the high initial cost, it is much better to have two small boilers than one large boiler. Heating capacities are judged on what the coldest outside temp the system may have to heat against. In my area this is usually around 7degrees F. But in an average year we may only actually experiance that low temp for ten total hours. For the rest of the year you have a (figuratively speaking) big 18 wheeler diesel running to satisfy a demand that a little four cylinder import motor can just as easily satisfy. See? With two boilers and a good control that will alternate which boiler starts first you have a heat plant that is very efficient, and reliable. As long as it was installed correctly (not that again!).
With your air conditioning, the 18seer units from Trane work on the exact same principal as I explained with the boilers previously. The condensing unit contains two compressors, one is smaller than the other. On a call for a/c the small compressor kicks in first. If after a while this compressor cannot keep up with the heat gain in your home, then the larger compressor kicks in and runs until the call for a/c is satisfied. It is very important/ and beneficial to have long run times when there is a call for a/c, the reason why is that the longer the compressor can run the more humidity will be removed from your home....this is when you really start to feel comfy. When an a/c unit is sized bigger than necessary the compressor quickly cools the home and shuts off before getting a chance to remove much humidity. With a variable speed airhandler, we can introduce a "dehumidify" function will will slow the blower speed to reduce output of the a/c unit and keep it running to remove moisture in the home...this is a nice feature- well worth the money, yep you guessed it...AS LONG AS IT IS DONE RIGHT!!!!!

Hopefully I answered some of your questions. What I hope you get from my rantings is the understanding that the first thing I think you should do is find the best contractor first (many you have already found right here!), then talk about high efficiency equipment with all the bells and whistles!!!!!

I wish you good luck, and hope you enjoy your new home!

Casmo

Sarwat Patel

Question on LP

Your points were excellent, they really will help me evaluate the choices presented to me in variuos bids. I absolutely agree, the key is to find the best man for the job. I am hoping to decide on that soon.

Here is my question: Given the fact that I will have propane tank buried in the yard and fitting and piping in the house to support teo professional cooktop, three self contained fireplaces, two grills outside and the dryer. (And given that I have chosen the best man for the job and I realize that oil gives me more for the buck). Do I add more exposure by choosing it for heating or I already have the exposure wiht it being in the house. If this was your house, what would be the choice.

Use LP for heating and deal with one fuel system, deliveries, tanks etc, and have some feeling of comfort that it may not be the cheapest but it is better for the environment.

Use oil irrespective and keep both fuel for the variuos purposes.

Cosmo

Hope this helps

You have absolutely no more exposure by adding a gas fired boiler to all the other appliances. Actually, the boiler will be the safest propane appliance you have, many safety features. As far as a return on cost of installing the oil tank, and separate fuel bill it is hard to say. How many years do yo plan on staying, what do you pay for propane, or oil in your area. I am not sure how much you will be using the other prpane appliances, but the boiler will be the main demand. One option is this, most any oil boiler can be converted to prpane with an appropriate gas-gun. This is a burner that burns gas/propane with a similar fire pattern to an oil boiler. Buderus, Viessman are sold both ways from the factory. You may try a cost analysis to see how long it would take to save the cost of installing the oil tank, etc. You are also right as far as conveniance, why pay another bill, but it is probably worth it. I'm not the right person to ask my opinion on fuel choice if all other things are equal....when I was 9 my father fired up an old oil burner in the shop to show me what the flame looks like and I have been hooked ever since!!!!! Ah the memories.....

Cas

joel_14

oil vs propane

Ok for starters I agree with every one else here as to the hydro air versus hot air debate no question hydro air is more comforable and gives you a myriiad of heating options that you simply can't achieve with hot air.

Now oil versus propane here's why it's so exspensive .
Oil contains 140,000 BTU of potential heat per gallon.
Propane contains 93,000 BTU per gallon.
So propane has 50% (aprox) less energy in it for every gallon you buy versus oil. This means that it would have to be 50% cheaper per gallon to be worth it.
Now some gas guys from the west are going to say Propane has higher eff and thier right the best oil equipment is 87-89% eff versus propane which tops out about 95% on the best equipment. This is at most a 7% increase which doesn't even begin to offset the lower energy available in propane. Lets put it this way every year we get calls from people asking to be switched from Propane to oil because of the cost. I've never had anybody ask to switch back. the cost of an oil tank is minimal ,in Mass the added cost would be saved back in just acouple of months. You can still have propane for cooking this is very common in the North East.

Steve Ebels

My $50,000 worth

HHHhhmmmmm. Let's see. 6000 sq ft at probably 25 BTU's per sq ft would be 150,000 btu's for heat, add 30% for extra capacity for heating DHW and you'd have a boiler of about 200,000 to 225,000. Trouble is you need that amount only rarely so most of the time your boiler will be massively oversized. What to do? Well, you're debating lp vs. oil so here's my feeling on that. LP is the most expensive fuel, period. That said, One thing you can do with a residential sized lp boiler that you can't with oil is get it with a modulating burner. This means the burner fires only as hard as it needs to to maintain a given water temp. In effect at part load you're wasting only 10% of say 100,000 btu's instead of the same amount of the full firing rate. Svaes you money and makes LP a little closer in terms of operating costs.

Outdoor reset means the boiler will modulate the water temp according to how cold it is outside. The colder it is the hotter the boiler makes the water, always provideing just enough heat to maintain your comfort level.

Hydro air would be my choice hands down for more reasons than I could list here. Broadly speaking they would be versatility, reliabilty, expandability and the ability to heat your hot water with the same piece of high efficiency equipment.

Boiler of choice would be Viessmann Vitodens.

Air handler of choice would be Enerzone if you can manage the standard size duct or Unico if you need small hi-velocity duct.

A/C condenser would be American Standard in a medium efficiency model. 13 SEER or less. You spend WAY more time heating the house than you do cooling it in Conn. so invest the money for the high grade equipment there. If you were in Arizona it would be different.

The basement floor would be radiantly heated. You can't heat a basement comfortably with forced air of any kind. It just won't stay down there.

Pick a good contractor. Check as many references as you can and live happily ever after.

oilwizard

hydro air no way

You want ducts, use them for for a/c. You want heat, go radiant or baseboards. Hydro air is scortched air any way you look at it. It is dusty and uneven type of heat. It heats up quick but cools off quick. Polens and dust get blown around everytime the fan comes on. You want humidity, add in a whole house humidifier. The other things people say is corrrect, find a good contractor, asks for references, don't take the builders word. As for oil or gas, I have installed both, far fewer for gas heat then oil up in the Northwest corner of CT, but some. BUrying a tank no big deal, talks should be protected from corrision if installed correctly, also if the company purged the tank correctly befor they delivered it to your property then you shouldn't have a problem with regulators freezing up in the winter, but it happens, even if you get a delivery with a high moisture content. Doesn't happen a lot but I have seen it. Finding a good tech to service lp is something else, most guys are afraid of gas, don't understand it. If you have a good lp company that shouldn't be a problem, but I can tell you some stories of some CT companies. OIl would be my choice. You can still bury a 120 fo the cooking and log sets, by the way, are you going to use a dual fuel range, gas for the cook top but go with an electric oven, gives a better stability of temp for baking, gas makes the temp go up and down to much because it heats up to quick. Oil dealers are plenty of, they bend over backwards to get and keep your buisness, I'm guessing if you look at the ratio of oil vs lp companies in your area oi will win big time, so I hope you can see where I'm going with this. One good thing about gas is the service would be less, but with oi if something breaks on the burner a part is usually on the truck, lp most companies don't stock parts because each man. is different so parts would need to be ordered, but a part faailing on gas is less likely then oil. Gas problems are mostly electrical, oil is both electrical and fuel related, not both at the same time, you know what I mean. A hot water system if installed correctly can be done so that you would not hear any sounds from the pipes when it runs, with constant circ and outdoor reset. These are just my views, use them or ignore them but the bottom line is research who you have for an installer and supplier and that would cut back on a lot of problems in the future for you.
Joe Buchas
Terryville, CT

Jacob Myron_4

Hydro air Vs hot air

The heating medium for both is fan blown hot air.

There is no difference in the heat you will get.

Hot air sytems use a fiurnace and heat exchangers that are heated by the hot flue gases leaving the furnace.

Hydro air uses steam or circulating hot water produced in a boiler and piped to a fan coil unit that blows the hot air into your rooms.

What ever system you install remember this one fact, moving air across the skin of your body has a cooling effect on your body.

If you want to spend the dollars you will have a greater comfort in your house if you installed a properlly designed steam heating, hot water or radiant heating system.

These systems do not have fancy names but provide heat with out drafts...

Jake

joel_14

i beg to differ

With the last two posts. Yes, radiant or hydronics is much better than any air based system. However putting a schorched air furnace in the same barrel as hydro air is 100% not accurate. In most cases in the Northeast we are talking about oil fired systems. with oil fired hot air it is extreemly difficult to have seperate zones, your only choice for hot water is an oil fired water heater which is short lived and exspensive, it's very hard to expand the system at a later date. Oil furnaces tend to have issues with getting odors into the ductwork as the air to your home is going right through them. Hydro air eliminates all of these issues and gives you many more options such as radiant zones for the bath which wouldn't be possable with straight hot air. is it the best??? No but if iwas choosing between the two the answer would be simple, esp if my fuel was oil!