Feeding heat pump hot water heater with minisplit heat

[incinerator]

So i bought a cheap'ish Turbro 12k btu 240v minisplit off amazon this past summer. Installed this fall. I have a couple year old 50 gallon heat pump hot water heater in the basement. I installed the minisplit head about 5 feet away from the water heater and the goal was to provide heat to a room in the basement and to provide heat to the hot water heater. No other heat source is in the basement. So far so good. The heat pump hot water heater has never switched over (to all electric) yet this winter and it has been cold here in Wisconsin. Also last winter i had an issue with the coils frosting up very badly--no issue this winter. I will say we've had to space out showers at times (family of 5). In the morning 3 can easily take a shower and be fine. IF i did it over i'd go with a 80 gallon tank just because of family size. I do have it set to 130F and have a mixing valve i want to install so i can set it at 140F. Its pretty neat to think that the heat in the tank is coming from outside all winter, although I doubt the COP of this setup is that great at very cold temps. In summer the hot water heater pretty much cools/dries the basement so its win-win.

I only bring this up because i've seen outdoor units that heat water...this is basically doing the same thing (but not as efficiently?) Much cheaper i would guess (Turbro model qualified for tax credit)--$500 into it..Heat pump hot water tank was cheap home depot deal i found ($700 at the time). Just thought i'd share.

 

[EbS-P]

Good solution. I did the math once if you run a cop of 2 for the mini split and a cop of 4 for the water heater that’s That’s two units of hot water at a cost of 1.5 units of electricity or COP of 1.33. Did I do that right? Pump two units of heat inside the house at a cost of one unit of electricity then those two units of heat into water cost .5 units of electricity. This would be for the coldest weeks of the year.

When it gets really cold I just fire up the basement woodstove. (It’s all finished space a living room and 3 bedrooms.) then I just heat my water with wood running my HP water heater.

 

[incinerator]

Good solution. I did the math once if you run a cop of 2 for the mini split and a cop of 4 for the water heater that’s That’s two units of hot water at a cost of 1.5 units of electricity or COP of 1.33. Did I do that right? Pump two units of heat inside the house at a cost of one unit of electricity then those two units of heat into water cost .5 units of electricity. This would be for the coldest weeks of the year.

When it gets really cold I just fire up the basement woodstove. (It’s all finished space a living room and 3 bedrooms.) then I just heat my water with wood running my HP water heater.

Yeah i'm not great at math but sounds right. I view my warm month hot water as free. The Turbro was pumping out 112F heat at -15F outside temps. Coldest temp so far this year. Lots of days below 0F. I've got 2 more minisplits on the main floor that run all winter and use the woodstove (1st floor) on the coldest nights. It was 3F outside this morning and 77F on the 1st floor! Lol. In July i keep it like 68F in here.

 

[EbS-P]

In the winter our inlet water temps drop considerably. I put it in hybrid mode this winter. If we run out of hot water I best go sleep in the playhouse. The 33% saving might not be worth the slow recovery time.

 

[incinerator]

In the winter our inlet water temps drop considerably. I put it in hybrid mode this winter. If we run out of hot water I best go sleep in the playhouse. The 33% saving might not be worth the slow recovery time.

I'm on a well where i am. The water is always cold but does vary some thru the year. Usually in the low 50Fs. When i put that mixing valve on i'm hoping we'll have more buffer. It also doesn't help that my kids seem to take showers that are 20 minutes too long.

 

[brenndatomu]

I installed a HPWH a few years back and it is basically "wood powered" in the winter...our Kuuma wood furnace is about 15' away and the "waste heat" coming off the furnace is what keeps the basement from getting too cold. I put an 8" duct elbow on the discharge of the HPWH pointing in the general direction of the Kuuma, there is strong airflow between the furnace and the HPWH when either machine is operating...if I hang a strip of TP in the doorway between the 2 it will hang at about a 30*(+) angle toward the HPWH, due to the airflow.
If I go into the menu on the HPWH and look at the ambient air temp it runs 75*+ when the furnace is rocking, closer to 60-65* when its not...oh, and I also put an extension on the intake of the HPWH so that it pulls in the warmest air off the ceiling too.
In the summertime the HPWH keep the basement dehumidified well enough that it does the job about 98% by itself...pretty happy with it overall.

 

[incinerator]

I installed a HPWH a few years back and it is basically "wood powered" in the winter...our Kuuma wood furnace is about 15' away and the "waste heat" coming off the furnace is what keeps the basement from getting too cold. I put an 8" duct elbow on the discharge of the HPWH pointing in the general direction of the Kuuma, there is strong airflow between the furnace and the HPWH when either machine is operating...if I hang a strip of TP in the doorway between the 2 it will hang at about a 30*(+) angle toward the HPWH, due to the airflow.
If I go into the menu on the HPWH and look at the ambient air temp it runs 75*+ when the furnace is rocking, closer to 60-65* when its not...oh, and I also put an extension on the intake of the HPWH so that it pulls in the warmest air off the ceiling too.
In the summertime the HPWH keep the basement dehumidified well enough that it does the job about 98% by itself...pretty happy with it overall.

My house heat is minisplits plus a 1st floor woodstove. Very little of the 1st floor heat though gets into the basement so i needed another source of heat down there so i just put a cheap split to cover it. I would say the downside to minisplits is they put out very mild warmth...usually i see temps of around 112F---not like a woodstove that can put out massive heat. I'd love to move the woodstove downstairs but the piping would be a nightmare.