There is individual called John Siegenthalet that writes columns for several magazines, he is a heating guru and big advocate of low temperature radiant emitters or radiant panels. I found this free webinar that may be helpful https://www.pmmag.com/events/910-fre...dronic-systems. If you have net metering and no annual reset, the way to go is put in more PV build up a credit and use a minisplit. Flat Plate SHW is not a great idea for heating as you have all sorts of heat in summer when you dont need it and not enough in the winter when you do. At best you get 80 degree rise over the outdoor temp and at 20 degrees that only 100 degrees out at best. Unless you put in lot of radiant panels or a radiant slab the temps just not hihg enough for most heating applications. Far better to spend money on having an energy audit and picking way at high air infiltration points first and then go after typicla poorly insulated spots like box sills in basements and the sill plates.
Far better to build up credit from net metering and then use the KW with the minisplit.
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Thanks for your feedback. Insulation is certainly on my list. How much to insulate is part of the 'cost' equation, as it has diminishing returns.
The heat mass can be used to store 'free' heat from solar, but I agree i also have to figure out how to not lose that heat to the outside.
So were do I start in figuring out how much insulation I need and determining a sweet spot with solar system/storage tank?Leave a comment:
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If you are cost and efficiency conscious, know that thermal mass by itself is of little use without insulation. The two are not the same. A well insulated and sealed space with little thermal mass will have HVAC bills that are about the same as an equally well insulated and sealed space with lots and lots of thermal mass. A poorly insulated space with a lot of thermal mass will have bills close to those of a poorly insulated space with lots of thermal mass. The key to low heat loss is insulation, not thermal mass. Buildings with equal HVAC requirements can often get by with smaller equipment capacities if the building has a lot of thermal mass and large mass buildings sometimes seem a bit more comfortable with fewer hot/cold spots.Currently/original house is a lot home, heated/cooled by a Fujitsu 36K mini-split.
Basement (900 sq feet) was built with radiant floors in mind (5 pex loops). Basement insulated with Superior Xi walls (estimated to be R9, see link below)
New addition was built, including basement. Basement floor was also prepared for radiant heating (9 pex loops.. about 800sq feet)
Not sure why loop count is different, no good answer there.
New basement outside block is 12", mostly filled with concrete (it holds a heavy garage on top).
Both floors have some insulation at bottom (estimating 1")
I have all the totals on how much concrete was used, as I have receipts
I also have some flat plate solar panels (7 units of 3x5)
The new space is bare block walls, only painted inside outside for water protection.
The idea was to take advantage of thermal mass..
House does have a 10k Solar array facing south. It's working out rather well (only have bills nov-mar, averaging below 150$.. not heating new space yet)
I am a little efficiency obsessed, but also want to have a system have a reasonable payoff
Initially I thought of getting a wood boiler.. but it seems very expensive and overkill for my application.
Now I am leaning towards drainkback solar with Backup (for simplicity, maintainability, and being DIY friendly), with backup being a super efficient (4-5COP) Sanden water heater
Discounting the fact that this setup may not be 100% supported by the manufacturer.
What's my path to figure out what I really need?
E.g. how do I calculate taking advantage of heat mass.. how do I determine what R value I will need to add to all walls.. how do I determine what storage outside of concrete I need (e.g. solar tank), how do I determine that what I am thinking is a good option.
Thanks,
R9 reference.
http://www.greenbuildingadvisor.com/...superior-walls
Spend your money and effort on insulation and a tight building envelope. A massive concrete wall has a very high heat transfer coefficient compared to that of an insulated frame wall of equal dimension.Leave a comment:
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Where do I start with Solar heating
Currently/original house is a lot home, heated/cooled by a Fujitsu 36K mini-split.
Basement (900 sq feet) was built with radiant floors in mind (5 pex loops). Basement insulated with Superior Xi walls (estimated to be R9, see link below)
New addition was built, including basement. Basement floor was also prepared for radiant heating (9 pex loops.. about 800sq feet)
Not sure why loop count is different, no good answer there.
New basement outside block is 12", mostly filled with concrete (it holds a heavy garage on top).
Both floors have some insulation at bottom (estimating 1")
I have all the totals on how much concrete was used, as I have receipts
I also have some flat plate solar panels (7 units of 3x5)
The new space is bare block walls, only painted inside outside for water protection.
The idea was to take advantage of thermal mass..
House does have a 10k Solar array facing south. It's working out rather well (only have bills nov-mar, averaging below 150$.. not heating new space yet)
I am a little efficiency obsessed, but also want to have a system have a reasonable payoff
Initially I thought of getting a wood boiler.. but it seems very expensive and overkill for my application.
Now I am leaning towards drainkback solar with Backup (for simplicity, maintainability, and being DIY friendly), with backup being a super efficient (4-5COP) Sanden water heater
Discounting the fact that this setup may not be 100% supported by the manufacturer.
What's my path to figure out what I really need?
E.g. how do I calculate taking advantage of heat mass.. how do I determine what R value I will need to add to all walls.. how do I determine what storage outside of concrete I need (e.g. solar tank), how do I determine that what I am thinking is a good option.
Thanks,
R9 reference.
Leave a comment: