Radiant or Geothermal Heat?
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Mavrik02
Silver Member
If I recall correctly the quoted price on our house was about $35k. It included heat and AC. The house is 2100 sq ft for basement and same for first floor with another 900 sq ft for the second floor.
I ended up paying about $22k for my HVAC work (radiant in basement/master bath, forced air gas, forced air electric, and two AC systems).
I ended up paying about $22k for my HVAC work (radiant in basement/master bath, forced air gas, forced air electric, and two AC systems).
Piedmont3
Silver Member
Yes, That was the total price. It included the wells, the ductwork, a 40 gal water storage tank, the water furnace unit, 4 zones, 4 thermostats, 4 return air ducts and filters and covers, and grill covers for the ducts, everything. We just got our bill yesterday for electricity from Oct 29 to Nov 29, it was $89.63. We are very pleased with the system.
HobbleCreek
Silver Member
That's good to know. How deep did they have to drill the wells?
Piedmont3
Silver Member
Our Pipes/loops are in 6 each 4" diameter wells that are 115 feet deep.
Got2BTru
Silver Member
Just wanted to say THANK YOU for this thread...keep it going! We're hopefully building on 32 acres next Spring in CNY. I'm currently looking at hydronic radiant heat (solar powered heater) and have contemplated geothermal, but doubt I'll have the $$$ for it. Just gotta figure out how to COOL the house in the summers.
Got2BTru,
Check the geothermal. I'm in CNY and have had it for 15 years now and its cheaper than you think especially if you can do some of the work your self. If your moving to what is really central NY your in for a big weather change from TX:0)
Check the geothermal. I'm in CNY and have had it for 15 years now and its cheaper than you think especially if you can do some of the work your self. If your moving to what is really central NY your in for a big weather change from TX:0)
Got2BTru
Silver Member
Thank you, I will. We're building the house in 2 phases next year. First is a 4 car garage with an "in-law" suite above it. We'll then move in there and once everything is paid off, then we'll start the main house. In between there will be a barn, etc. so it may be a couple of years.
As for CNY, I grew up in CNY, so I know what it's like. I left in my early 20's & spent 5 years in the Carolinas and 15+ in the Dallas area. TOO HOT for me...that's why we're in the process of moving back and building up in CNY.
As for CNY, I grew up in CNY, so I know what it's like. I left in my early 20's & spent 5 years in the Carolinas and 15+ in the Dallas area. TOO HOT for me...that's why we're in the process of moving back and building up in CNY.
JCByrd24
Gold Member
This is excellent advice. Buildings built properly today with these principles in mind do not need complex and expensive systems like geothermal and even radiant to be comfortable. A residence can be easily built in any climate the can be heated/cooled primarily with mini split heat pumps at cost a fraction of any of the systems mentioned in this thread. The money can be spent on insulation and then renewable energy to approach net zero rather than forking out thousands on systems that still required you to buy the energy.
Raspy
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Well, radiant is not an expensive way to install heat in a home if it's simply PEX tubing buried in concrete. Second, it's not complex either. Third, it is the most comfortable heat delivery system there is. There is no way a mini-split system will match the comfort of a radiant floor. As far as whether it's geothermal OR radiant, as the OP asked, I'd like to point out that radiant is the best way to deliver Geothermal because radiant operates at the lowest temperature.
In my case, I did not need air conditioning, so that is not a factor in the cost. But if it is in your case, you might be able to go with a simple, one zone system that will make it worth it. I understand combining the heat and cooling into the same ductwork seems like a savings, but when walking around on a cold floor, you'll definitely be wondering if that was the right choice. The mini-split is efficient, but the floors are still cold.
Geo-thermal is appealing, but it is also an expensive and complicated system when compared to a simple active solar system delivered through in-slab radiant. I chose an oil boiler to make up for extended periods of bad weather with limited solar. This will still keep the radiant heat working. But in my case we never needed it last winter and ran on 100% solar. I don't like propane, but a small occasionally used propane boiler would be a fine backup too.
It's sad when builders tell their clients that they'll need supplemental heat because the radiant won't be enough. Hogwash. My clients have told me the radiant is their favorite part of their new house. No one with radiant chooses to use backup forced air systems.
Raspy,
Funny, I started this thread in 2005. We went with Radiant with an ele boiler. The heat is very good, quite. We have many zones so much of our home is un-heated when there are no guests.
I was planning on solar water heating to "feed" the radiant. Now I think I'm best off installing PV solar panels and get power 365 days a year. We have a 3000 sq-ft flat roof so plenty of room for a good size array.
Funny, I started this thread in 2005. We went with Radiant with an ele boiler. The heat is very good, quite. We have many zones so much of our home is un-heated when there are no guests.
I was planning on solar water heating to "feed" the radiant. Now I think I'm best off installing PV solar panels and get power 365 days a year. We have a 3000 sq-ft flat roof so plenty of room for a good size array.
JCByrd24
Gold Member
Paddy,
I would concur that your best bet these days is PV vice thermal solar. Like you said you can take advantage of the PV all year round. Thermal systems large enough to supplement heat are usually not of much use in the summer unless you want to heat a pool. Thermal is usually sized first for domestic water heating, but even for that purpose PV is getting very good.
Raspy, I concur that there is nothing really particularly complex about a radiant system in the world of typical home heating systems. That being said, in a modest new construction project the quote for a minisplit or two and some supplemental electric baseboards will be likely well under $10K, possibly $5k. A radiant system + boiler will likely be well more, and in most of North America (even here in Maine) the bonus of free AC would be considered huge (I'm running AC right now in my bedroom). If you added some sort of AC to the radiant system it would likely just be a minisplit anyway, at around $3k by itself.
There are numerous articles out that document the study of radiant heat in well (super) insulated homes. The science basically shows that the heat demand can easily be reduced by insulating far enough that the radiant system barely ever has to run, to the point where the floor never actually feels warm. Additionally, the make the point that the difference in comfort is basically unnoticeable. Having friends with super insulated homes, I can attest to the fact that they feel warmer than they are, much like a radiant heated house.
I've never heard anyone get a geothermal quote under $20K. For my money that is a PV array that produces power not just uses less.
I would concur that your best bet these days is PV vice thermal solar. Like you said you can take advantage of the PV all year round. Thermal systems large enough to supplement heat are usually not of much use in the summer unless you want to heat a pool. Thermal is usually sized first for domestic water heating, but even for that purpose PV is getting very good.
Raspy, I concur that there is nothing really particularly complex about a radiant system in the world of typical home heating systems. That being said, in a modest new construction project the quote for a minisplit or two and some supplemental electric baseboards will be likely well under $10K, possibly $5k. A radiant system + boiler will likely be well more, and in most of North America (even here in Maine) the bonus of free AC would be considered huge (I'm running AC right now in my bedroom). If you added some sort of AC to the radiant system it would likely just be a minisplit anyway, at around $3k by itself.
There are numerous articles out that document the study of radiant heat in well (super) insulated homes. The science basically shows that the heat demand can easily be reduced by insulating far enough that the radiant system barely ever has to run, to the point where the floor never actually feels warm. Additionally, the make the point that the difference in comfort is basically unnoticeable. Having friends with super insulated homes, I can attest to the fact that they feel warmer than they are, much like a radiant heated house.
I've never heard anyone get a geothermal quote under $20K. For my money that is a PV array that produces power not just uses less.
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Raspy
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JC,
Some good points there. It is interesting that, as you mentioned, the better insulated the house, the less radiant is needed and the floor never really feels warm. In those cases we're not merely trying to keep the house comfortable, but make the floor "invisible" and make it greet them in the morning. The beauty of radiant goes beyond the simple utility of satisfying a thermometer. So, timing it achieves pleasant surprises as it satisfies the heat load. Merely keeping the house a constant temp isn't really the goal as temp changes mean greater comfort and lower bills. Cool sleeping temps, warm bath floors in the morning, warm winter living rooms, cool unused rooms, etc.
Geothermal has never interested me personally with it's over the top complication and electric demand. But PV would help with that, even if it did add yet more hardware to do so.
Solar thermal, as you mentioned, cannot produce 100% of the required load. Mini splits might be a good supplement with their ability to cool too. As I write this we are in Scottsdale AZ, visiting. There is no way I could live here without AC. But in our home in northern Nevada, AC isn't needed. I ducted and wired for it, but I doubt I'll ever install the units and complete it.
PV seems to be really coming of age, but I can't decide which way to do it is best. Probably just research the equipment and do it myself. Our electric bill is so low that I can't justify it yet.
Some good points there. It is interesting that, as you mentioned, the better insulated the house, the less radiant is needed and the floor never really feels warm. In those cases we're not merely trying to keep the house comfortable, but make the floor "invisible" and make it greet them in the morning. The beauty of radiant goes beyond the simple utility of satisfying a thermometer. So, timing it achieves pleasant surprises as it satisfies the heat load. Merely keeping the house a constant temp isn't really the goal as temp changes mean greater comfort and lower bills. Cool sleeping temps, warm bath floors in the morning, warm winter living rooms, cool unused rooms, etc.
Geothermal has never interested me personally with it's over the top complication and electric demand. But PV would help with that, even if it did add yet more hardware to do so.
Solar thermal, as you mentioned, cannot produce 100% of the required load. Mini splits might be a good supplement with their ability to cool too. As I write this we are in Scottsdale AZ, visiting. There is no way I could live here without AC. But in our home in northern Nevada, AC isn't needed. I ducted and wired for it, but I doubt I'll ever install the units and complete it.
PV seems to be really coming of age, but I can't decide which way to do it is best. Probably just research the equipment and do it myself. Our electric bill is so low that I can't justify it yet.
Redneck in training
Elite Member
We have geothermal with floor heating in our house. If you are barefoot the floor feels cold even at very low temperatures outside. But if you put socks on it suddenly feels warm. We have set entry temperature to 90F. The heating has large time constant (1F per 2 hours) so messing with different temperature setting for occupied/unoccupied makes little difference.
The desuperheater on our unit is able to overheat hot water heater popping the safety. When weather got colder and AC stopped running there was not hot water until the safety was reset. Therefore I added a thermostat that stops desuperheater pump when maximum temperature is reached.
Since all our AC ducting is in attic we used fiberglass insulated ducts. They are very easy to install with only knife and special aluminum tape.
Our air handler for AC is Unico high pressure. We selected Unico because it is easy to install and it it much quieter than low pressure system. Only disadvantage is difficult integration with whole house ventilation/filter.
If I would build house today I would use mini splits and invest the saving in large PV system.
We heat about 3800 scft and AC 2400 sqft. Before we installed PV system we used to have two meters. One for heating only and the second for the whole house. Maximum heating charge (January) was about 90 USD at 4.8 cent/kWh.
The desuperheater on our unit is able to overheat hot water heater popping the safety. When weather got colder and AC stopped running there was not hot water until the safety was reset. Therefore I added a thermostat that stops desuperheater pump when maximum temperature is reached.
Since all our AC ducting is in attic we used fiberglass insulated ducts. They are very easy to install with only knife and special aluminum tape.
Our air handler for AC is Unico high pressure. We selected Unico because it is easy to install and it it much quieter than low pressure system. Only disadvantage is difficult integration with whole house ventilation/filter.
If I would build house today I would use mini splits and invest the saving in large PV system.
We heat about 3800 scft and AC 2400 sqft. Before we installed PV system we used to have two meters. One for heating only and the second for the whole house. Maximum heating charge (January) was about 90 USD at 4.8 cent/kWh.
Raspy
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Red,
For many years I've designed radiant systems with thin slabs over a standard subfloor. These have, in the bathrooms, tubing spaced on 6" centers. So the response is felt in minutes, instead of hours. It also means the cool down times are less and so, less overshoot. It also means that room thermostats have little value, but timing becomes more important, at least in the bathrooms and kitchen.
In my home I went the opposite direction to bring the floor temp up to just below where I might want it on average and then add some heat as needed. The 8" slab becomes a stabilizing factor and energy storage mass for solar. But even with this large mass, zoning allows a reasonable response time if the energy available is high enough.
In the Bay Area, in CA the heat loss I use is seven BTU/ sq. ft for a break even number. Ten BTUs will run a house OK, but the response is poor. Twenty-five works well even with one thermostat zone in the whole house, but when you have multiple zones, you might have 100 BTU/sq ft available or more for a given small zone. Then timing those zones with priority to lifestyle, such as warm bath at 7AM and warm living room at 6 PM, you can get excellent response. In those cases, "warm" does not mean the wall thermostat is satisfied, it means the floor feels warm and the air temp is relatively cool. It also means the boiler is not overloaded on small zones and can feed a given temp during the whole cycle. This gives excellent response and predicability. A delivery temp of 126 degrees instead of simply a few degrees per pass makes a big difference, even though the few degrees per pass will do the job eventually. And again, the room thermostat is an extremely poor way to run most systems. It only acts as a rough high limit that causes overshoot, especially in smaller zones.
I found a neighborhood with 756 homes that have radiant heat. They were built from the mid '50s to the mid '60s. All were set up the same with a 100,000 BTU boiler and one thermostat. Almost everyone I've talked to has the same complaint. Uneven heat, overshoot, high bills, cold rooms.
I can go into virtually any one of them and do the following: Even out the heat in all rooms, reduce the heating bill by at least $100.per month and eliminate the overshoot, which makes them far more comfortable. This is all done by improving the circulation rate, balancing the manifold, tuning up the boiler and installing a setback thermostat. Then I help them see how to re-think the heating process and realize that the thermostat is a poor measurement of comfort. Universally, they ALL praise the outcome of this process.
For many years I've designed radiant systems with thin slabs over a standard subfloor. These have, in the bathrooms, tubing spaced on 6" centers. So the response is felt in minutes, instead of hours. It also means the cool down times are less and so, less overshoot. It also means that room thermostats have little value, but timing becomes more important, at least in the bathrooms and kitchen.
In my home I went the opposite direction to bring the floor temp up to just below where I might want it on average and then add some heat as needed. The 8" slab becomes a stabilizing factor and energy storage mass for solar. But even with this large mass, zoning allows a reasonable response time if the energy available is high enough.
In the Bay Area, in CA the heat loss I use is seven BTU/ sq. ft for a break even number. Ten BTUs will run a house OK, but the response is poor. Twenty-five works well even with one thermostat zone in the whole house, but when you have multiple zones, you might have 100 BTU/sq ft available or more for a given small zone. Then timing those zones with priority to lifestyle, such as warm bath at 7AM and warm living room at 6 PM, you can get excellent response. In those cases, "warm" does not mean the wall thermostat is satisfied, it means the floor feels warm and the air temp is relatively cool. It also means the boiler is not overloaded on small zones and can feed a given temp during the whole cycle. This gives excellent response and predicability. A delivery temp of 126 degrees instead of simply a few degrees per pass makes a big difference, even though the few degrees per pass will do the job eventually. And again, the room thermostat is an extremely poor way to run most systems. It only acts as a rough high limit that causes overshoot, especially in smaller zones.
I found a neighborhood with 756 homes that have radiant heat. They were built from the mid '50s to the mid '60s. All were set up the same with a 100,000 BTU boiler and one thermostat. Almost everyone I've talked to has the same complaint. Uneven heat, overshoot, high bills, cold rooms.
I can go into virtually any one of them and do the following: Even out the heat in all rooms, reduce the heating bill by at least $100.per month and eliminate the overshoot, which makes them far more comfortable. This is all done by improving the circulation rate, balancing the manifold, tuning up the boiler and installing a setback thermostat. Then I help them see how to re-think the heating process and realize that the thermostat is a poor measurement of comfort. Universally, they ALL praise the outcome of this process.
