This is my first post here. I'm fixing up a ~1860s house in a rural setting in Upstate NY. As the house has ample land around it and electricity is the only hard-wired utility, I have been thinking that a geothermal heat pump would ultimately be an economical option for an HVAC system. I have three quotes that appear to have vastly different design philosophies. I'd like some opinions on how effective they might be for our application.

First, the statistics:

• 3500 square ft conditioned living space
• 1800 sq ft unfinished, unconditioned, walk-out dirt floor basement
• Complex geometry - the house is essentially two cubes, offset, forming distinct front and back sections.
• High 9-10' ceilings throughout, except for the back second story.
• 20 miles from Cortland, NY. 0°F 99% design temp, average winter temps dip to 14-27F. Records of around -32 or so.

Existing state of the house:

• The house has existing oil hydronic heat that may or may not work.
• Some cast iron radiators on first floors
• Some baseboard electric on first floor
• Second floor front section is heated entirely with electric baseboard
• Rear second story is heated with vents in the floor which merely let in heated air from the floor below
• Walls insulated in the 70s with fiberglass bats. Now infested with mice
• Basement stone walls have lots of above ground exposure

Additional background:

• While not a full gut rehab, we will be doing some significant demolition indoors of some of the non-original partition walls and dropped ceilings.
• We have one quote so far for insulating and tightening up the house. For ~20k, they claim the design heating load can be brought down from 124k BTU/hr to 47k BTU/hr. We are awaiting another quote. Oddly enough, they calculate 49k BTU/hr max cooling load once everything's done as well. I'm surprised it would be anywhere close to parity with the max design heating load.
• In BeOpt, I get 65k BTU/hr currently, down to about 52k BTU/hr with my approximation of what they're proposing, 40k BTU/hr if I'm overly optimistic about how much air sealing is possible.

Finally, here are the geothermal details of the three different quotes we have. If we can truly scale back the heating load to 47k BTU/hr, I'll have to ask about how downsizing would affect the price for some of these options. All assume horizontal loops.

1. Single 2-stage, 6 ton water to air. Zoned duct work to entire house with 4 zones, using metal chases from the 1st floor to the 2nd, and fiberglass duct board in unconditioned spaces (attic basement). 4 zones. Also includes hot water heater & desuperheater. Roughly $48k
2. Two 2-stage, water to air heat pumps: One in basement, one in attic. 5 and 2 ton. Duct work and hot water heater included. $15k for ducts, $35k for heat pumps, resulting in roughly $50k.
3. Water to water 2-stage 5-ton unit, with two hydronic air handlers, metal ducts, and buffer tank. $55k

My own comments:

• The nerd in me likes the decoupling of the heating/cooling source from distribution in (3), but I'm not sure I'm convinced if it's worth the premium $$$. I've read great things about the comfort of oversized air handlers, and a near constant flow of low-pressure, low-velocity, low-temperature air for heating.
• (1) calls for the most elaborate duct system, as there would be only one air handler. It also assumes the highest number of zones. I assume this can be done well, but I'd be concerned about being able to get the proper airflow to all ducts int he house under the many permutations of zoning calls, and heat pump stage.
• (3) may offer the opportunity to add radiant heat to bathroom floors at a later date for additional comfort, if we wanted to. We would have to use tubing under the floor.
• None of the proposals suggests conditioning the basement, which is fine with us for now. Maybe in the distant future we'd want to do something with it, but for now it'll just serve as storage.

So if anybody has any comments or opinions about my options so far (or other options I should explore), that would be very helpful. Despite reading through the forum archive, I don't think I can translate each of the proposals into a measure of performance satisfaction just yet.

they claim the design heating load can be brought down from 124k BTU/hr to 47k BTU/hr

Yeah - the difficulty right now is that blower door tests taken right now would be meaningless, as there are some holes directly to the attic where a a roof leak damaged drywall (the old structural framing is just fine). There are also no records of utility usage for the past 2 years. Estimating the current pre-improvement baseline is a bit of a shot in the dark. I'm not suspicious of them per se, it's just that the situation is a difficult one, and I'm on the lookout for patterns or consistencies between what various estimates say.

It is interesting that nobody suggested open loop. I can ask if they have experience in that area, and what their thought process was in not suggesting it

Posted By birkie on 29 Sep 2012 10:17 AM
Hello,

This is my first post here. I'm fixing up a ~1860s house in a rural setting in Upstate NY. As the house has ample land around it and electricity is the only hard-wired utility, I have been thinking that a geothermal heat pump would ultimately be an economical option for an HVAC system.

Hi,

I'm located in Newfield and I can tell you that in our area, especially in an older house, geo is a very economical option.  The system we put in last year will have less than a 7 year payback over oil.  We have a similar 1840's vintage home (though smaller than yours).  Obviously, do what you can within reason to get the heating load down first.  I sent you a pm with the name of the installer who did our system.  Highly recommend him if you're looking for other quotes.

Posted By birkie on 29 Sep 2012 10:17 AM
Hello,

I have three quotes that appear to have vastly different design philosophies.

Always more than one way.......as they say

First, the statistics:

• 3500 square ft conditioned living space
• 1800 sq ft unfinished, unconditioned, walk-out dirt floor basement
• Complex geometry - the house is essentially two cubes, offset, forming distinct front and back sections.
• High 9-10' ceilings throughout, except for the back second story.
• Lowered ceilings offer duct chase oppurtunity
• 20 miles from Cortland, NY. 0°F 99% design temp, average winter temps dip to 14-27F.
• Which one is it 14 or 27?
•  Records of around -32 or so.
• Records are for auxiliary heat to worry about and have little bearing on design

Existing state of the house:

• The house has existing oil hydronic heat that may or may not work.
• It would be nice to know condition of radiators particularly if you go water to water geo
• Some cast iron radiators on first floors
• Some baseboard electric on first floor
• Second floor front section is heated entirely with electric baseboard
• Rear second story is heated with vents in the floor which merely let in heated air from the floor below
• Walls insulated in the 70s with fiberglass bats. Now infested with mice
• Basement stone walls have lots of above ground exposure
• Good news a mouse nest has a pretty good R Value

Additional background:

• While not a full gut rehab, we will be doing some significant demolition indoors of some of the non-original partition walls and dropped ceilings.
• We have one quote so far for insulating and tightening up the house. For ~20k, they claim the design heating load can be brought down from 124k BTU/hr to 47k BTU/hr.
• Wouldn't suprise me if there was 80kbtu improvement available. The first 50 will be as easy as fixing broken windows, holes in the ceiling and making sure fireplace dampers (if any) are functional. In other words you are already going to accomplish much of the dimineshed load, so they are promising to save you another 20 to 30 kbtu beyond that.
•  We are awaiting another quote. Oddly enough, they calculate 49k BTU/hr max cooling load once everything's done as well. I'm surprised it would be anywhere close to parity with the max design heating load.
• We see this from time to time particulary in multistory homes (less heat loss than a ranch) with lots of windows (lots of gain) typical of older homes.
• Throw in the improved envelope and balanced loads are really not a suprise.
• In BeOpt, I get 65k BTU/hr currently, down to about 52k BTU/hr with my approximation of what they're proposing, 40k BTU/hr if I'm overly optimistic about how much air sealing is possible.
• With no other intell available, I think a load in the 50K range is probably realistic.
• I'm curious what load your geo designers selected.

Finally, here are the geothermal details of the three different quotes we have. If we can truly scale back the heating load to 47k BTU/hr, I'll have to ask about how downsizing would affect the price for some of these options. All assume horizontal loops.

1. Single 2-stage, 6 ton water to air. Zoned duct work to entire house with 4 zones, using metal chases from the 1st floor to the 2nd, and fiberglass duct board in unconditioned spaces (attic basement). 4 zones. Also includes hot water heater & desuperheater. Roughly $48k Not a fan of this bid as first it is probably oversized by 2 tons and then shoved through four zones of duct that would have to each be capable of 4 tons of airflow if no other zone were calling.
2. Two 2-stage, water to air heat pumps: One in basement, one in attic. 5 and 2 ton. Duct work and hot water heater included. $15k for ducts, $35k for heat pumps, resulting in roughly $50k. 7 tons I like less than 6. I also wouldn't be suprised if 2 tons were very marginal for the upstairs cooling load.
3. Water to water 2-stage 5-ton unit, with two hydronic air handlers, metal ducts, and buffer tank. $55k I like this, particularly if we are to provide domestic hot water with leftover capacity.

You could likely employ 5 tons of WTA as well an go with 2 zones (1 up one down). I'd have to know elec rates and exact loads before I endorsed a particular size, but gut says 5 ton.

Are you in Doc Jensers AO by any chance?

My own comments:

• The nerd in me likes the decoupling of the heating/cooling source from distribution in (3), but I'm not sure I'm convinced if it's worth the premium $$$. Price difference between low and high bid only about 15% and low bid has a bad plan and one less appliance. Middle bid within 10% and may also be a bad plan. Not my definition of "premium".
• I've read great things about the comfort of oversized air handlers, and a near constant flow of low-pressure, low-velocity, low-temperature air for heating. Without knowing what you read (context) all I can say is "oversized" anything is often bad design. Right sized geo is already known for constant, even temperatures
• (1) calls for the most elaborate duct system, as there would be only one air handler. It also assumes the highest number of zones. I assume this can be done well,You may presume too much but I'd be concerned about being able to get the proper airflow to all ducts int he house under the many permutations of zoning calls, and heat pump stage. I'd be concerned with restricted air flow, noisey operation etc.
• (3) may offer the opportunity to add radiant heat to bathroom floors at a later date for additional comfort, if we wanted to. We would have to use tubing under the floor. By far the most elaborate design once you see all that's involved.
• None of the proposals suggests conditioning the basement, which is fine with us for now. Maybe in the distant future we'd want to do something with it, but for now it'll just serve as storage. My experience is a conditioned basement costs little more than duct in an unconditioned space.

So if anybody has any comments or opinions about my options so far (or other options I should explore), that would be very helpful. Despite reading through the forum archive, I don't think I can translate each of the proposals into a measure of performance satisfaction just yet.

Can't you temporarily plug the holes in the damaged ceiling areas with some scraps?

You need to spend more money and thought on improving the overall construction and envelope and less on the heating plant.

• 20 miles from Cortland, NY. 0°F 99% design temp, average winter temps dip to 14-27F.

Which one is it 14 or 27?

It would be nice to know condition of radiators particularly if you go water to water geo

1. Single 2-stage, 6 ton water to air. Zoned duct work to entire house with 4 zones

Not a fan of this bid as first it is probably oversized by 2 tons and then shoved through four zones of duct that would have to each be capable of 4 tons of airflow if no other zone were calling.
...
I'd be concerned with restricted air flow, noisey operation etc.
...
You could likely employ 5 tons of WTA as well and go with 2 zones (1 up one down)

I would like to know what each of the installers considered the heat loss to be.

Price difference between low and high bid only about 15% and low bid has a bad plan and one less appliance. Middle bid within 10% and may also be a bad plan. Not my definition of "premium".

Are you in Doc Jensers AO by any chance?