Furnace vs mini splits

[stoveliker]

Just as an anecdotal data points, I'm running the mini split now in addition to the basement stove (stove does fine at 0 F, but 5 F and 40 mph wind is tough).
This is not a hyperheat.
At 10 F.it was blowing 110 F air quite consistently.
At 5 F it was blowing 109 F air (max; it depends on the cycle towards defrosting, other times it was 100-105).

It raised the temps inside the home easily by 2 degrees. (Despite multiple defrosting cycles).

I think the cop of this one at 7 F is 2.1, so I did likely use quite some kWhs (but I have plenty of those in my solar bank so I don't care).

 

[gthomas785]

I have a 12k BTU mini split and an Emporia energy monitor. The power use depends on how hard it's running which depends on the delta between room temp and set temp. When it's really cranking it pulls about 800-900 watts. When it's closer to set point and dialed down it pulls between 200-400 watts.
In heat mode the defrost cycle draws close to 1 kW for 3-4 minutes.

 

[EbS-P]

But on the sprinter forum they telling me everyone in NE is freezing because heatpumps don’t work when it’s cold😉

I need to add a mini split or two. The kitchen is the longest run. It’s too warm in the summer. And the basement is to cool in the winter. It’s either a dual head or two singles. I need to they won’t ever run at once so a dual head 12k unit with two 12k heads is what I want. But they don’t like to sell that as a DIY kits.

 

[gthomas785]

But on the sprinter forum they telling me everyone in NE is freezing because heatpumps don’t work when it’s cold😉

I need to add a mini split or two. The kitchen is the longest run. It’s too warm in the summer. And the basement is to cool in the winter. It’s either a dual head or two singles. I need to they won’t ever run at once so a dual head 12k unit with two 12k heads is what I want. But they don’t like to sell that as a DIY kits.

Honestly you'll get a bit more efficiency from two single zone units than one dual zone. The price of the equipment is usually similar. If you have space for two outdoor units I'd go that way.

 

[John Galt]

Thanks for all of the input! I really appreciate the real world data. I think I’ve looked at every possibility and settled on a solution that will work for us now and in the future.

I’m putting in two Mitsubishi 20k hyper heats systems with 9k and 12k dual ceiling cassette heads each. That will supply 40k BTU upstairs, mostly in the 1200 sq ft open space living area. There will be another identical 20k system in the basement to supply a bedroom and the “Tavern”. I will also install a propane ducted furnace upstairs. All of this is in addition to the BK King upstairs and the Princess in the basement. Overkill? Yep. Dealing with everything I can think of? Yep. Expensive? Yep.

The stove will be used for deep winter, rainy days, and ambiance. The splits for shoulder seasons and cooling. The furnace for backup, when we’re out of town, or when I’m older and feebler. The basement never drops below 55 in the winter, and never gets above 63 in the summer. The split downstairs would heat the bedroom in the summer for guests that like it a bit warmer and to take the chill off whenever we’re shooting pool.

The King heats the house until the temps go hard negative, and I’m still air sealing before the drywall goes up. That’s 38k BTU per the literature. I figure that the splits will just cruise along when it’s 30 outside but I might build a fire in the evening when they get shut down. Each 20k split only burns 1500W so I can decide how many to turn on and when.

I decided not to do the floor furnaces since I would need two and at that point it’s about the same cost as running ducts to every room. A dual fuel system would require one big heat pump using 3.5k-4k Watts which takes all of the flexibility out of the system and would limit the time it could be used. The cost is in the same range as having separate systems.