heat pump + stove advice

[aircooledRN]

Hello,

I have bought a home this year with a wood stove in the basement (DS Energy MAX 160) and a heat pump as the only sources for heat. I have some experience burning wood for heat, our previous accommodations was a basement apartment with a wood stove that we used to heat the apartment.

My plan this winter is to try and heat 100% with the wood stove in the basement, my question is more along the lines of the heat pump. Can I efficiently use it as a back up to the wood stove? for times when the stove isn't burning and we are not home? I have read the the lowest a heat pump should be set is 68-70. however, I would like for the heat pump to run as minimally as possible. Would having it set at 68-70 while burning be enough to keep it from running? or am I better off turning it off while we burn?

For reference house is a log cabin with registers in the floor for the woodstoves heat to rise. And I am located in NE Ohio where our winters usually dont get too crazy cold.

Apologies in advance if this has been touched one before, I tried looking but did not find this specific question answered.

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[begreen]

Welcome. It's ok to set the heatpump thermostat lower. The heatpump could be set at 65º without harm. It will just take it longer to heat the place up if it does get called on for heat. What is the heat pump make and model? Does it have resistance heater coils in it for colder weather heating?

Heating with wood from the basement in this stove is going to take a fair amount of wood. Is the basement insulated?
Do you have several cords of wood that are fully seasoned (split and stacked for a couple years)?

 

[aircooledRN]

I am unsure of the heat pump make and model, I can look tomorrow when I get home from work. The house was built in '01. I do have a couple cords of wood that have been split for at least 1 year. along with quite a few logs that have been cut but just not split that have been siting for the same amount of time.

My goal is to lower the electric bill as much as possible during the winter month since we have the stove.

 

[begreen]

Are the basement walls insulated? If not, the heat loss will be high. That translates into much higher wood consumption.

It's probably ok to use the heat pump for general heating until outside temps drop below 40º without hammering the electrical bill. Usually a heat pump is pretty good on low energy consumption until outdoor temps reach the crossover point where it switches to resistance heater coils. At that point, the meter really spins.

 

[aircooledRN]

The basement walls are block. so I assume they are not insulated?

Before I used a simple stove in the living room, with this stove would flash burning not be an option?

 

[begreen]

The basement walls are block. so I assume they are not insulated?

If the walls are uninsulated then the heat loss through the block will be significant. About a third of the wood burned will be sucked out of the room to heat the ground on the other side of the walls.

Before I used a simple stove in the living room, with this stove would flash burning not be an option?

Explain. Is there a stove currently in the LR? If so, what is the stove model and what is flash burning?

 

[aircooledRN]

The stove mentioned was in a previous place. This house we moved into this year and only has the stove in the basement. Flash burning is just making one fire and filling the stove and letting it go out after it finishes burning. rather than keeping it going all day.

 

[Caw]

We live in MA and have an older Trane X-13 heat pump 2006 installed in our 1984 two story cape. It has resistance coils that will kick on below 37 degrees outside. Our primary heat comes from an Osburn 1600 insert on the first floor in the living room which is also where the staircase is located to go upstairs.

The stove does 99% of the work in the winter. We set the heat pump to 63 as a back up and it only comes on a few times a year when the temperatures dip below 5 degrees overnight. I know it will go right to the backup coils so setting it to a lower heat target temp doesn't matter. I can either get up at 4 am and add wood or just allow the coils to go for a couple hrs. It depends on how tired I am but we only get those temps a week or two out of the winter so either way it's not a big deal.

I think a heat pump and stove is an ideal combo. I get efficient electric heat in shoulder season and then my stove does all the work in the winter. I have solar panels too so the heat pump runs basically for free. The only time I'm spending any real money is when the panels are covered in snow and if the back up coils kicks on.

 

[vatmark]

I have never heard that the lowest you can set a heat pump is 68-70. We have a Trane heat pump and set it to 62 at night in the winter and thats with not using any other heat source. We like to sleep cold. I will even crack our sliding door in the bedroom open. But we also live in NC so it doesnt get crazy cold here. When we use our woodstove I keep our bedroom door closed so the room doesn't get too warm. We have an open floor plan so when the woodstove is going the heat wont come on because the thermostat is out in that area. I don’t see why you cant just set your thermostat lower to prevent it from kicking on. I dont think I would turn it off.

 

[stoveliker]

I think that advice comes from not wanting to dial up the Tstat so much that the actual temperature is more than 4 degrees below the setpoint (because it would switch on the auxiliary heat - the resistance coils).
So if you want the home at 73 during the day, don't go lower than 69 at night.

This may be advice or older systems though- not sure if this still holds for current whole house (ducted) heat pump systems.

 

[aircooledRN]

I have never heard that the lowest you can set a heat pump is 68-70. We have a Trane heat pump and set it to 62 at night in the winter and thats with not using any other heat source. We like to sleep cold. I will even crack our sliding door in the bedroom open. But we also live in NC so it doesnt get crazy cold here. When we use our woodstove I keep our bedroom door closed so the room doesn't get too warm. We have an open floor plan so when the woodstove is going the heat wont come on because the thermostat is out in that area. I don’t see why you cant just set your thermostat lower to prevent it from kicking on. I dont think I would turn it off.

The setting of a heat pump at that temp is just where the peak efficiency for the heat pump is at. from talking with HVAC techs. Going lower your not getting as much efficiency from the heat pump.

But I also do not want the heat pump running if I'm burning at the same time. I guess as long as I am burning and the temp is above 68 it shouldn't kick on.

 

[Caw]

I know on my heat pump I can set it to use the auxiliary resistance heat only too. That's not something you'd want to do regularly but if it's very cold out and you're only using it for back up that's an option.

As I said above though I tend to set it to between 63 degrees during burning season so the house never gets colder than that. If the temp dips overnight it'll kick on at like 4 or 5 am for an hr or two and the onboard computer will realize it's below 37 outside and kick on the auxiliary resistance strips.

I have an ecobee smart thermostat and a temp sensor in every room which I find incredibly helpful for wood burning...especially since the main thermostat is located in the stove room. I can program which rooms I want to use for temp averaging which will determine when the backup heat comes on. I usually pick the 3 coldest rooms in the house (kitchen, den, dining room) and go based off those 3 that way it's never colder than 63 anywhere in the house. Then in the summer I do the opposite and pick the warmest rooms when I run the AC.

I love my heat pump / stove combo. After getting solar panels installed it's even better. I get two efficient ways to heat my home without burning fossil fuels and I'm in full control of each with next to no utility bill exposure. For living in the middle of suburbia it's about as off the grid as you can get.

 

[aircooledRN]

I know on my heat pump I can set it to use the auxiliary resistance heat only too. That's not something you'd want to do regularly but if it's very cold out and you're only using it for back up that's an option.

As I said above though I tend to set it to between 63 degrees during burning season so the house never gets colder than that. If the temp dips overnight it'll kick on at like 4 or 5 am for an hr or two and the onboard computer will realize it's below 37 outside and kick on the auxiliary resistance strips.

I have an ecobee smart thermostat and a temp sensor in every room which I find incredibly helpful for wood burning...especially since the main thermostat is located in the stove room. I can program which rooms I want to use for temp averaging which will determine when the backup heat comes on. I usually pick the 3 coldest rooms in the house (kitchen, den, dining room) and go based off those 3 that way it's never colder than 63 anywhere in the house. Then in the summer I do the opposite and pick the warmest rooms when I run the AC.

I love my heat pump / stove combo. After getting solar panels installed it's even better. I get two efficient ways to heat my home without burning fossil fuels and I'm in full control of each with next to no utility bill exposure. For living in the middle of suburbia it's about as off the grid as you can get.

Solar is something I would like to add eventually but comes at a large starting cost. this is our first winter heating a full house with wood and with this woodstove. So I know a lot of trial and error are ahead. I will look into that thermostat, having sensors in other rooms interests me.

 

[Caw]

Solar is something I would like to add eventually but comes at a large starting cost. this is our first winter heating a full house with wood and with this woodstove. So I know a lot of trial and error are ahead. I will look into that thermostat, having sensors in other rooms interests me.

Yeah it cost about $23,000 after rebates but it covers 90% of my electrical needs so I'll break even after year 6.

Here's what my thermostat app looks like, I can control everything HVAC with my phone which is convenient. They aren't that expensive and make heating with wood + back up a lot easier.

 

[aircooledRN]

Yeah it cost about $23,000 after rebates but it covers 90% of my electrical needs so I'll break even after year 6.

Here's what my thermostat app looks like, I can control everything HVAC with my phone which is convenient. They aren't that expensive and make heating with wood + back up a lot easier.

View attachment 283971

Thats a pretty steep price tag, unsure if that's something i would want to do in a house I'm not 100% sure I am staying in for 5+ years.

 

[begreen]

The setting of a heat pump at that temp is just where the peak efficiency for the heat pump is at. from talking with HVAC techs. Going lower your not getting as much efficiency from the heat pump.

But I also do not want the heat pump running if I'm burning at the same time. I guess as long as I am burning and the temp is above 68 it shouldn't kick on.

That's correct.

 

[Caw]

Thats a pretty steep price tag, unsure if that's something i would want to do in a house I'm not 100% sure I am staying in for 5+ years.

Oh it's almost certainly not worth it for that short a span. You MIGHT get your money back on resale but it wouldn't be a sure thing. When people ask me about solar I usually say if you intend to be there for at least the next 10 years then it makes financial sense as most systems pay for themselves within 5-7 years.

 

[peakbagger]

Or you live in an area that allows DIY solar. Equipment costs have come way down and there is lot of used equipment out there. Used panels are available in the 50 cents a watt range. Used inverters (a riskier buy) can be had for less 1/3 of the cost of new. Labor is a big cost of solar (that is not going down) but that is not a factor with a DIY install. Racking will need to be bought new in most cases as buying new means it can come with PE stamped structural design required by many jurisdictions. Local jurisdictions may require an electrician to do the final hookup as there are some limits on system wattage related to the electrical service.

Ideally a array built with used components gets built on a non occupied structure or ground mount so Rapid Shutdown requirements do not have to be met but even on a house, used microinverters can be used (with more risk due to their higher failure rate). A buck an installed watt is a reasonable target.

BTW Solar panels do not wear out, they just lose some output efficiency, throw in a few extra panels and the lost efficiency is made up pretty quickly. Inverters on the other hand do wear out, the general rule of thumb is 10 years thus buying a used inverter is risky.

 

[aircooledRN]

Welcome. It's ok to set the heatpump thermostat lower. The heatpump could be set at 65º without harm. It will just take it longer to heat the place up if it does get called on for heat. What is the heat pump make and model? Does it have resistance heater coils in it for colder weather heating?

Heating with wood from the basement in this stove is going to take a fair amount of wood. Is the basement insulated?
Do you have several cords of wood that are fully seasoned (split and stacked for a couple years)?

Heat pump is a Rheem Classic 10 Seer heat pump, unsure on year.

 

[begreen]

Heat pump is a Rheem Classic 10 Seer heat pump, unsure on year.

Sounds like an old, single-stage unit that's not very efficient. If electric bills are high in the winter it is probably switching over to re$i$tance coil heating at a relatively high outdoor temperature. Your plan of setting the thermostat at 65 or 68 and using the wood stove is the best short term solution as long as you have an adequate supply of good, dry firewood on hand. Make sure the stove flue system is clean and ready for the season.

PS: Your Avatar profile shows your location as Cochabamba96. Where is this?

 

[aircooledRN]

Sounds like an old, single-stage unit that's not very efficient. If electric bills are high in the winter it is probably switching over to re$i$tance coil heating at a relatively high outdoor temperature. Your plan of setting the thermostat at 65 or 68 and using the wood stove is the best short term solution as long as you have an adequate supply of good, dry firewood on hand. Make sure the stove flue system is clean and ready for the season.

PS: Your Avatar profile shows your location as Cochabamba96. Where is this?

Cochabamba is a City in Bolivia. However, I live in NE Ohio.

 

[begreen]

Cochabamba is a City in Bolivia. However, I live in NE Ohio.

Thanks, that helps us understand the heating needs better.