HVAC: What's best for cold climates?

[Sbob]

I'm leaning toward heat pump with propane backup and wood backup backup.

Honestly if I am going to have ducts, I think I might as well go for a standard heat pump (no mini-splits). The mini-splits are a good solution in a renovation when ducks are a PITA. But this is new construction and I don't like the look of the mini-splits inside the house.

The cheapest way to back it up with propane looks to be a furnace that drives forced air through the same ducts, but the hot setup looks to be furnace with hydro baseboards.

Costs TBD of course.

Have you figured out how you want to heat your domestic hot water? They have tankless units that do both domestic and hydronic. You can install a hydro coil downstream of your heat pump air handler.

A word about using fossil backup heat with a heat pump. Shutting off your heat pump below 40°
My auto mechanic called me because his heat pump wasn’t working after running his wood stove all winter. There was a lot of snow on the ground, I walked around the corner of his house to see his unit had self destructed.
Seems the blades were full of snow and quite out of balance. It flung a chunk of ice into the coil and the refrigerant leaked out. Also all the screws holding the fan in place came out and the fan did a ton of damage.
Some brands have a cover on top that prevents snow from getting inside.
A lot of people use the heat pump at lower temperatures to prevent buildup of snow and ice. They’re more efficient than they used to be.

 

[Harvey]

Have you figured out how you want to heat your domestic hot water? They have tankless units that do both domestic and hydronic. You can install a hydro coil downstream of your heat pump air handler.

We actually own a Rennai tankless hot water heater. We could use it. I installed it at the cabin because we didn't have room for a tank, and also I can drain the system fast. The only downside I see is that it is a bit of a trick to get the shower temperature right. The temperature fluctuates so you have to be careful. My guess is we'll use propane to heat a water tank, unless you have a better idea.

A word about using fossil backup heat with a heat pump. Shutting off your heat pump below 40°

My auto mechanic called me because his heat pump wasn’t working after running his wood stove all winter. There was a lot of snow on the ground, I walked around the corner of his house to see his unit had self destructed.

Seems the blades were full of snow and quite out of balance. It flung a chunk of ice into the coil and the refrigerant leaked out. Also all the screws holding the fan in place came out and the fan did a ton of damage.

Some brands have a cover on top that prevents snow from getting inside.

A lot of people use the heat pump at lower temperatures to prevent buildup of snow and ice. They’re more efficient than they used to be.

I think we would put a small roof over the heat pump.

If I can't get a heat pump that works below 40 degrees it might not make sense. I see units advertised (well) below that and don't totally trust those numbers, hence the propane back up. If the heat pumps rated to -13F are good until 10 above, I'm guessing it will probably work out.

 

[x10003q]

I'm leaning toward heat pump with propane backup and wood backup backup.

Honestly if I am going to have ducts, I think I might as well go for a standard heat pump (no mini-splits). The mini-splits are a good solution in a renovation when ducks are a PITA. But this is new construction and I don't like the look of the mini-splits inside the house.

The cheapest way to back it up with propane looks to be a furnace that drives forced air through the same ducts, but the hot setup looks to be furnace with hydro baseboards.

Costs TBD of course.

You could put the split units in the ceiling. This is a clean install.

Ceiling Cassette Mini-Split AC & Heat Units | Mitsubishi Electric HVAC US

Ceiling cassette mini-split units are a stylish heating and cooling solution with custom airflow configurations to swiftly and evenly heat and air condition.

www.mitsubishicomfort.com

 

[Harvey]

Google just asked me if I wanted to try AI. I said yes. If I get taken over by space aliens, please feel free to save me.

For now, it seems pretty good.

Runtals are expensive. I had a guy price out Runtals for my house and it was over 10 grand for the parts. I wondered if there were other attractive hydronic baseboards that might be cheaper. I found this pretty quick:

Burnham Baseray Cast Iron Baseboard Radiator – 2′ Wide

www.consumersplumbing.com

Anyone ever seen it, or know anything?

 

[Sbob]

Google just asked me if I wanted to try AI. I said yes. If I get taken over by space aliens, please feel free to save me.

For now, it seems pretty good.

Runtals are expensive. I had a guy price out Runtals for my house and it was over 10 grand for the parts. I wondered if there were other attractive hydronic baseboards that might be cheaper. I found this pretty quick:

Burnham Baseray Cast Iron Baseboard Radiator – 2′ Wide

www.consumersplumbing.com

Anyone ever seen it, or know anything?

I saw a Runtal sample over the summer and thought they looked nice from the front but lots of nooks and crannies for dust bunnies to hide in the back.

Regular cast iron baseboard is nice but expensive. I don’t think it’s very aesthetic but that’s me .

Go radiant in floor, more bucks but no more cold feet. You might need additional heat if you go with hardwood. Max floor temperature is 80°

 

[Sbob]

We actually own a Rennai tankless hot water heater. We could use it. I installed it at the cabin because we didn't have room for a tank, and also I can drain the system fast. The only downside I see is that it is a bit of a trick to get the shower temperature right. The temperature fluctuates so you have to be careful. My guess is we'll use propane to heat a water tank, unless you have a better idea.



I think we would put a small roof over the heat pump.

If I can't get a heat pump that works below 40 degrees it might not make sense. I see units advertised (well) below that and don't totally trust those numbers, hence the propane back up. If the heat pumps rated to -13F are good until 10 above, I'm guessing it will probably work out.

Add a mixing valve downstream of your tankless heater and problem solved.

Minis and inverters adjust airflow for warmer discharge air vs regular heat pumps when it gets really cold.

 

[Harvey]

Sbob you ever use this to size Heat pumps?

Air Conditioning Contractors of America - ACCA

ACCA (Air Conditioning Contractors of America) is the association of HVAC (heating, ventilation, air conditioning, building performance) contractors.

www.acca.org

 

[Sbob]

Sbob you ever use this to size Heat pumps?

Air Conditioning Contractors of America - ACCA

ACCA (Air Conditioning Contractors of America) is the association of HVAC (heating, ventilation, air conditioning, building performance) contractors.

www.acca.org

I use a program called HVAC Calc . Radiant jobs I give to my Wholesaler .

 

[gorgonzola]

Google just asked me if I wanted to try AI. I said yes. If I get taken over by space aliens, please feel free to save me.

For now, it seems pretty good.

Runtals are expensive. I had a guy price out Runtals for my house and it was over 10 grand for the parts. I wondered if there were other attractive hydronic baseboards that might be cheaper. I found this pretty quick:

Burnham Baseray Cast Iron Baseboard Radiator – 2′ Wide

www.consumersplumbing.com

Anyone ever seen it, or know anything?

Ive replaced a few old style radiators in my house with those, they work good but they aint cheap and you need alot of length to get enough output - I had hoped to use it in my latest bathroom reno but there wasn't enough wall space.

Thanks for the reminder I need to hook up that radiator back up this fall!

 

[riverc0il]

If I can't get a heat pump that works below 40 degrees it might not make sense. I see units advertised (well) below that and don't totally trust those numbers, hence the propane back up. If the heat pumps rated to -13F are good until 10 above, I'm guessing it will probably work out.

My Mitsubishi mini-split doesn't do well below 40 degrees. I go to primary heating (electric) in my unit during the winter. Works awesome until it gets close to freezing, then the efficiency really falls off. We have three floors and an in-wall unit on each floor, but per condo policy, they cannot be considered a primary heat source for the unit.

Which is fine, we primarily got them for cooling and drying during the summer. Heating during the fall/spring is just a bonus. They are super efficient... my electric bill (which is quite low for this region) only went up $30-40/month during the summer (we only run it when we are uncomfortable).