Building an 8000 sq ft house-need HVAC advice

gee-ess

I am in a dilemma! I was planning to put in a geothermal system in our new home (3800 main floor, 1300 second, 3500 basement) but in our area the reviews of this system are mixed. It is a lot of money to invest in a system that people are not overwhelmingly positive about. I would love to have some honest responses about this system. My second choice is a heat pump/LP furnace combo. I would also like some advice on the latest heat pump technology so that if I choose this route I can maximize my efficiency and not have outrageous electric bills. I have a 12 year old heat pump now and don't really love it but don't have any problems other than I am constantly kicking it up where the heat strips come on! Thank you!

PJO_4

How About...

Water to water geothermal with radiant? You get the benefit of non-polluting geothermal, and the wonderful comfortability of radiant heat.

Water Furnace International is one place to start. I believe Earthfire, among others, can chime in here.

Hope this helps. Take Care, PJO

Justin Gavin

Where do you live?

I guess it depends where you live.

What is your climate like? Also look at the expected cost of running the system (whichever you choose) over the course of the time you expect to live in the home. I am assuming that you live where natural gas is not an option.
Have you considered fuel oil as an option?
It might take you several years to get a return on investment on the geothermal unit. When you consider the cost of repair and replacement over a reasonable period of time you might be better off with a conventional boiler system. A properly designed fuel oil boiler system will more efficient than a LP furnace because fuel oil is a better source of fuel when it comes to btu output per gallon. 144,000 btu's per gallon of fuel oil compared to 95,000 btu's per gallon of LP.

If you are concerned about the environment you have other options available,

1. a solar water heater for a majority of the year with a conventional fuel oil or lp boiler for the secondary heat (when needed). You could couple the hot water side of things with an air handler for second stage heat. That way the air handler can be connected to a condenser for AC.

I don't know much about geothermal to give you any help there so I won't even try. I just am trying to open your mind to other options.

I wish you the best of luck.

Best Regards,
Justin

Mark Eatherton1

Boy....

did YOU happen upon the right site.

There will be LOTS of questions that will show up that YOU need to answer. Can't get the truth withoutit...

There is NO right thing to do things wrong.

Been a long week...

ME

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Mike Kraft_2

Heat and Cool

The one comment that was made is what is your climate?Good question.What will the construction of the home be?Exterior surfaces..........several choices.Will the extra expense of addressing air infiltration on the envelope be made?Example being foaming the inside joints of framed exterior walls and framed plates.Or is this a post and beam where the exterior surfaces will be steskin panels?If infiltration is going to be addressed a heat recovery vetliation system will be needed.Indoor air quality is a very big issue in tight envelopes.

As far as how to heat.Geo is certainly a very big investment with a home of this size.I am not involved in geo so I have but an uneducated opinion:)Seems assumptions are very available in todays market(G).But your climate is key.If you have a large amount of cooling days in the year I would consider it.Running expense and service is a factor also.As is the heat pump.Heat pump's have a large place where I live in the HVAC market.Our KW/HR is .07/HR.

How important is your comfort long range for heating?Hydronics have quite a wide versatile array of options to choose from.Including heating air to be blown through ducts.Once a hydronic heating appliance is installed it can warm you in such a large variaties of ways.Or did I say that:)It also offers you a most efficient way to heat your domestic water with a tank that can virtually last a lifetime.You mentioned LP for heat pump back-up.There are several gas fired wall hung conmdensing boilers available today that will bring you in the low to mid 90% efficiency level.

You sound like you are walking a line.An 8,000 sq' home is a lot of home to heat and cool.It seems that like so many the temptation of scorching air and cooling through the same emitters is a budget pleaser.Remeber..........hind sight is 20/20.Listen to these guys and don't place your comfort in the utilitarian closet.........it's more important than an esthetic!It's gonna be there a long time.Do it right.

cheese

Constantin

Really depends on location

Geothermal heat pumps are the bee-knees, as long as you can keep the install costs to sub-stratospheric levels. For our application, I'd have to drill a deep well and all the other fancy footwork to make geothermal work on a urban plot. Drilling around here is very expensive ~10K for a 350' deep well.

One guy told me to budget between 25-35K just for the drilling, HX unit and install (not even ductwork). At that point I can buy some pretty darn efficient air-air HX units, and still have money left over to insulate the house properly. For our neck of the woods, the payback on getting the house buttoned-up properly certainly seems to be better than that of a heatpump.

However, I'm perfectly willing to be proven wrong. I'm just a homeowner who made a couple of calls, not a heating-expert. If your house is in the countryside, you can either dig a well, run the tubing through the yard, or install a open loop system. All of them are likely to be much less expensive than the urban units simply because of the cost of living and the lack of competition for things like well-drilling in this area.

t.speed

geothermal

Having worked on the hydronic and DHW load side and brought into the engineering phase of several large water to water resdiential geothermal systems, a critical question to ask is the soil conditions of the geothermal field. For geothermal to work and to justify the large up front cost, a close balance of heating and cooling loads MUST be present. If not, the field temperature could be raised or lowered over many years and greatly affect efficiencies. Another consideration is the projected maintenance cost: pump and component replacement. Price a back-up heat source also. Look at a 30 year operating scenario. What does all this cost and how much energy is saved? Then calculate your pay-back (and conventional fuels may look better). Insist on hard data from a third party that you can comprehend. Water to water geothermal works but all those nasty up-front costs may outweigh the benefits.


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S Ebels

Let's see........... options options everywhere

Geo heat pump using a well(s)

Geo heat pump using a ground loop(s)

Geo heat pump using open loop (pump&dump)

Any of the above driven a ducted system

Any of the above driving a combo duct/radiant floor system

Any of the above with a fuel driven heating backup

Any of the above with an electric backup

That's enough to get me confused, but wait there's more

Air to air, and air to water type HP's are also available. Much less expensive to install, lower comfort level and usually higher operating cost.

Now a whole nuther' set of choices to contemplate would be what you can do with a boiler as a heat source. Along with that would be how A/C will be addressed. Any boiler system MUST be installed for low temp <150* operation, for best efficiency. Forced mechanical ventilation with heat recovery is mandatory for best system efficiency also.

Confused yet?

Seriously though, each home is different due to location, construction details, heat loss, heat gain, DHW demand, climate, HO preferences, air infiltration levels and R-values, ad-infinitum. (Is that a word?)

Our collective advice will only be as good as the info you can provide about all of the above. We all enjoy getting someone on the right path to comfortable, healthy, efficient homes so have at it.

gee-ess

the details

Okay - here are a few more details concerning my house.
I live in se missouri. Average winter temp is in the high 30's but definitely have temps in the teens. Summers are hot and humid. I worry about keeping the 2nd floor cool.
Our lot is 5 acres
Oil is not a fuel source readily available in this area
I am not sure what my kw elect costs are but the general consensus among everyone is that our elec costs are reasonable to low. My current 4500 sq ft house (2400 main, 2100 basement) home averages 175.00 per month.
We would be using a closed loop system with horizontal loops.
My other alternative is air pump with LP furnace in combination.

Dave Yates (PAH)

If geothermal

is a serious consideration and you'd like to see SEER ratings that can match or slightly exceed the energy conservation of geo, then you might consider installing "standard" heat pumps - sized to accomodate the heating (not cooling) load while coupling that up to a water storage tank. A 12-SEER unit can easily become a 24-SEER unit by utilizing water instead of air as the heat exchange medium.

The outdoor unit "sees" only the tank, so short cycling and being oversized for the coling load don't matter. You can then zone hydronically to smaller air handlers. We built our own from scratch two years ago & made it a four-zone system for A/C. We utilized a 55-gallon indirect for the storage and installed a DX flat plate heat exchanger for the freon to water heat transfer. No well drilling needed!

I'm off next week to Atlanta to learn about the new inverter technology being used in just a few heat pump models (it's coming on strong - IMHO.) The incoming single phase current is converted to three phase, which allows for full modulation - just like the Munchkin boiler! We just finished an installation in a photo lab/studio with three small wall mounted indoor air handlers. When first turned on, the outdoor unit learns which size unit is connected - one at a time as the two communicate through low voltage DC current wiring (just two wires needed due to it being DC). Once that's accomplished, outdoor and indoor reset is utilized to ramp BTU production and fan speeds up or down as needed. Any combination of the three indoor units can operate & the outdoor unit (single refrigeration circuit) will immediately adapt to the load. No strip heating required. Very quiet too. No ductwork with room by room zoning!

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Ken D.

Geo Thermal

I have serviced many GT systems over the years,although I have never installed one. I speak from a serviceman's viewpoint. These systems must be engineered and installed correctly. Here you get too many conflicting opinions from different engineers, different installers, different well guys,architects, servicemen, yada, yada, yada...... How is a home or building owner supposed to make a learned discision when the professionals can't agree? I speak from experience. Open systems- The wells must be able to handle the capacities required for proper operation. We had one job with two engineers who swore the system would work. First the well would not yield the needed water. Two wells- the return well would not handle the returning water, causing overflow. Three wells- Pump out of one pump into two. Still get overflow in certain conditions. The one engineer and architect almost got into a fist fight over it. Of course they took the usual out. They blamed the installer, who was just following orders. I still go by that house in the winter and see the the hillside covered with ice from the overflowing water. The cost to the homeowner was tremendous. One phenomenon I encountered with a closed loop field system. After extended running which is all the time in season, the soil(which is a poor heat conductor) in the field had a tendency to hold the cold in the winter and the heat in the summer, causing the efficeincy to fall way off. I finally spoke to an engineer who agreed thats what was happening. Of course the designing eng. would have none of it. his design said the system worked fine regardless of what the thermostat said. Meanwhile the residents are not comfortable. Another pitfall was when I went on a job only to find out the installer put in toxic antifreeze into a closed loop system. At the homeowner's expense We removed the toxic stuff and installed non-toxic. Luckily there was no leaks underground or there could have been an enviromental disaster the homeowner would have to deal with, especially when there was no city water available. Because the water in many open loops is hard or corrosive extra water treatment is required to prevent system deterioration. Another expense. I have had larger systems that the heat exchangers leaked into the refrigerant side, requiring extensive clean up and in some cases a new unit. Which is the cost effective way to go in my opinion Another job comes to mind, The supply piping in a 10,000 sq.ft. house was too small. They did not get enough flow to operate properly. Of course the designing installer, who was not a engineer, Refused to admit he screwed up. "That system works" he said. Tell that to the homeowners. Once the house is finished, Reworking pipes and ducts is a major problem and expense. Maintenance is a concern. Water filters must be changed regularly. If provisions for this are not provided, the system must be purged each time or upgrade at customers expense. Leaks must be dealt with in a timely fashion to prevent the myriad of problems down the road. Cases like these plus the initial costs of installation makes me wonder of the true savings these systems provide. As a serviceman, I am very gun shy about getting in the middle of these battles,and will not get involved if it appears to be a quagmire. The customer ends up with a system noone wants to touch. Where there are plenty of systems that do work OK, be very careful when deciding.
When they work, they work but, problems can be enormous.

jerry scharf

> is a serious consideration and you'd like to see

> SEER ratings that can match or slightly exceed

> the energy conservation of geo, then you might

> consider installing "standard" heat pumps - sized

> to accomodate the heating (not cooling) load

> while coupling that up to a water storage tank. A

> 12-SEER unit can easily become a 24-SEER unit by

> utilizing water instead of air as the heat

> exchange medium.

>

> The outdoor unit "sees" only

> the tank, so short cycling and being oversized

> for the coling load don't matter. You can then

> zone hydronically to smaller air handlers. We

> built our own from scratch two years ago & made

> it a four-zone system for A/C. We utilized a

> 55-gallon indirect for the storage and installed

> a DX flat plate heat exchanger for the freon to

> water heat transfer. No well drilling

> needed!

>

> I'm off next week to Atlanta to learn

> about the new inverter technology being used in

> just a few heat pump models (it's coming on

> strong - IMHO.) The incoming single phase current

> is converted to three phase, which allows for

> full modulation - just like the Munchkin boiler!

> We just finished an installation in a photo

> lab/studio with three small wall mounted indoor

> air handlers. When first turned on, the outdoor

> unit learns which size unit is connected - one at

> a time as the two communicate through low voltage

> DC current wiring (just two wires needed due to

> it being DC). Once that's accomplished, outdoor

> and indoor reset is utilized to ramp BTU

> production and fan speeds up or down as needed.

> Any combination of the three indoor units can

> operate & the outdoor unit (single refrigeration

> circuit) will immediately adapt to the load. No

> strip heating required. Very quiet too. No

> ductwork with room by room zoning!

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 98&Step=30"_To Learn More About This

> Professional, Click Here to Visit Their Ad in

> "Find A Professional"_/A_

jerry scharf

jerry scharf

jerry scharf

> is a serious consideration and you'd like to see

> SEER ratings that can match or slightly exceed

> the energy conservation of geo, then you might

> consider installing "standard" heat pumps - sized

> to accomodate the heating (not cooling) load

> while coupling that up to a water storage tank. A

> 12-SEER unit can easily become a 24-SEER unit by

> utilizing water instead of air as the heat

> exchange medium.

>

> The outdoor unit "sees" only

> the tank, so short cycling and being oversized

> for the coling load don't matter. You can then

> zone hydronically to smaller air handlers. We

> built our own from scratch two years ago & made

> it a four-zone system for A/C. We utilized a

> 55-gallon indirect for the storage and installed

> a DX flat plate heat exchanger for the freon to

> water heat transfer. No well drilling

> needed!

>

> I'm off next week to Atlanta to learn

> about the new inverter technology being used in

> just a few heat pump models (it's coming on

> strong - IMHO.) The incoming single phase current

> is converted to three phase, which allows for

> full modulation - just like the Munchkin boiler!

> We just finished an installation in a photo

> lab/studio with three small wall mounted indoor

> air handlers. When first turned on, the outdoor

> unit learns which size unit is connected - one at

> a time as the two communicate through low voltage

> DC current wiring (just two wires needed due to

> it being DC). Once that's accomplished, outdoor

> and indoor reset is utilized to ramp BTU

> production and fan speeds up or down as needed.

> Any combination of the three indoor units can

> operate & the outdoor unit (single refrigeration

> circuit) will immediately adapt to the load. No

> strip heating required. Very quiet too. No

> ductwork with room by room zoning!

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 98&Step=30"_To Learn More About This

> Professional, Click Here to Visit Their Ad in

> "Find A Professional"_/A_