Alternative heat source, minisplits for real?

[georgepds]

....
These things are several thousand dollars. 2-3 for the unit and then who knows how much for install. I hate hiring people but this skillset is very unique.

Re hiring...

I could only find an HVAC firm to install the units if I bought it from them. it requires two trades: electric and HVAC

 

[georgepds]

When this this is in “balls out” mode to make heat how is the sound level? Like a refrigerator, woodstove blower, or hair dryer?

There is no sound inside or out. The only way I can tell if it is running is if I stand in the breeze

I really would not believe me, since my hearing sucks, but my wife, who can hear a 120 mm computer fan in a 1/2" pine cabinet,says the computer fan is louder

If all she could hear was a fan, I'd be golden, But she can hear a low level fart at 50 m, which does me in every time

 

[begreen]

Its -1 here now outside and I did run the unit to test the cold weather output and its still cranking out great heat. According to a chart in the install manual its running at about 70% capacity. At -13 it cuts out but is still running at 5 0%. What will be interesting to see is above 44 degrees it will actually put out 130%+ of its rated output.

Fantastic for such an inexpensive little unit. Our normal winter temps are in the low 40s so this would work very well out here.

 

[maple1]

There is no sound inside or out. The only way I can tell if it is running is if I stand in the breeze

I really would not believe me, since my hearing sucks, but my wife, who can hear a 120 mm computer fan in a 1/2" pine cabinet,says the computer fan is louder

If all she could hear was a fan, I'd be golden, But she can hear a low level fart at 50 m, which does me in every time

There is no doubt it's running, when putting heat out. Full speed & max heat is fairly loud if you are near it. But just maintaining, it varies between lower amounts.

Best for someone to find one & hang out next to it for a while if they are definitely concerned about it.

(Our floor mount is a lot quieter than the wall mount though, it seems).

 

[peakbagger]

I do want to point out that even though the units may be putting toasty air down to zero that the efficiency is getting close to electric baseboard. IMHO the air movement required to move the air around increases the comfort temperature due to the convective cooling from the breeze. I think folks are far better running radiant baseboard or other alternatives when the temps get down to 10 F or lower but every house will be different. On both my Mitsubishi units, there are three setting for fan speed. Low is quite quiet, far quieter than a window AC unit. Medium is noticeable but not objectionable, high is definitely noticeable and I have to turn up my TV volume to compensate. I find that when I run the unit on high I am mostly trying to get the heat to move around the house farther from the unit. In real cold weather the farther rooms get decidedly colder.

The other thing to keep in mind is these devices do not magically change the laws of physics. If you selected mini splits to meet the design heat load like a furnace there would be several of them lined up next to each other. These are really just fan forced space heaters, great for supplement heat but not so good for a primary heating system.

I do like mine and recommend them to a lot of folks but get worried that some folks listed to the hype and think that they are a viable substitute for a primary heating system in cold climates, they aren't but they sure make a great supplement especially for folks who are now starting to see a need for AC where they used to not need it.

 

[Tegbert]

I heat a 25x30 ft area (one Fujitsu 12k RLS heat pump per floor, one head per floor). I arranged the pumps so that they blow in through the BR doors.If you want a cooler BR, close the doors. If you want a warm but not hot BR, leave the door open a tad

Don't know if you count it as a big area, but each pump keeps each floor toasty, ( Well, not quite toasty in this 3F weather, more like 68F inside). In the summer they will cool everything . The big red arrows show the rough airflow. You can feel the breeze in the BR when you stand in the doorway,. FWIIW, the heat pump heads have louvers so that you can direct the air

I do run the four fans in the winter to stir things up. I measured considerable stratification in the second floor cathedral room ( ~ 1F/ft) until I turned on the fans. On the first floor the fans are used more to stir up the hot air from the wood stove. Because the thermometer is in the head, you want to make sure the pump is at or near the same temperature as the ground. I mount mine ~ 8 feet high
View attachment 238818

That’s a decent area but In my house it is about 25’ wide by 64’ long. I see how yours does make it work though I just don’t see one head unit in my home making the far reaches comfortable without overheating the room it’s in. I mean my insert can make the far reaches comfortable and bearable heat in that room so maybe it’s possible. Just would be more efficient in my eyes to split it up more.


Lopi Rockport
Blaze King Ashford 25

 

[Tegbert]

I do want to point out that even though the units may be putting toasty air down to zero that the efficiency is getting close to electric baseboard. IMHO the air movement required to move the air around increases the comfort temperature due to the convective cooling from the breeze. I think folks are far better running radiant baseboard or other alternatives when the temps get down to 10 F or lower but every house will be different. On both my Mitsubishi units, there are three setting for fan speed. Low is quite quiet, far quieter than a window AC unit. Medium is noticeable but not objectionable, high is definitely noticeable and I have to turn up my TV volume to compensate. I find that when I run the unit on high I am mostly trying to get the heat to move around the house farther from the unit. In real cold weather the farther rooms get decidedly colder.

The other thing to keep in mind is these devices do not magically change the laws of physics. If you selected mini splits to meet the design heat load like a furnace there would be several of them lined up next to each other. These are really just fan forced space heaters, great for supplement heat but not so good for a primary heating system.

I do like mine ands recommend them to a lot of folks but get worried that some folks listed to the hype and think that they are a viable substitute for a primary heating system in cold climates, they aren't but they sure make a great supplement especially for folks who are now starting to see a need for AC where they used to not need it.

So if you recommend not getting rid of the baseboard heat then what would you do in place of them? Meaning like my baseboards take up a lot of wall space that I would like back for furniture or other things that I now have to keep clear. If they end up being equivalent to baseboard heat in lower temps do they just do a poorer job of heating a space? My goal is to rid the house of baseboard heat and in the PNW I think most of our weather would be ok with using just them.


Lopi Rockport
Blaze King Ashford 25

 

[maple1]

I don't find baseboards take much space away. If you say back a couch up against a wall, the top will hit the wall way before the bottom will hit the baseboard - then just pull it back out an inch or so. If it's something else straighter like a shelf, not a big thing to ease it up against the baseboard. I have some narrow strips of boards in the odd place laying on the floor under the baseboard to stop something from being shoved in too hard against them.

Also, a heat pump will send heat out across a space a lot further than a stove will. They can really move air if you bump the speed up.

 

[maple1]

I do want to point out that even though the units may be putting toasty air down to zero that the efficiency is getting close to electric baseboard. IMHO the air movement required to move the air around increases the comfort temperature due to the convective cooling from the breeze. I think folks are far better running radiant baseboard or other alternatives when the temps get down to 10 F or lower but every house will be different. On both my Mitsubishi units, there are three setting for fan speed. Low is quite quiet, far quieter than a window AC unit. Medium is noticeable but not objectionable, high is definitely noticeable and I have to turn up my TV volume to compensate. I find that when I run the unit on high I am mostly trying to get the heat to move around the house farther from the unit. In real cold weather the farther rooms get decidedly colder.

The other thing to keep in mind is these devices do not magically change the laws of physics. If you selected mini splits to meet the design heat load like a furnace there would be several of them lined up next to each other. These are really just fan forced space heaters, great for supplement heat but not so good for a primary heating system.

I do like mine ands recommend them to a lot of folks but get worried that some folks listed to the hype and think that they are a viable substitute for a primary heating system in cold climates, they aren't but they sure make a great supplement especially for folks who are now starting to see a need for AC where they used to not need it.

Depends on the definition of 'cold climate'. Based on our experience so far, I think I could do all our heating (2700 broken up square feet) with 3 12k heads. Down to at least -20c intermittently. For less fuel cost than anything except wood. If I was going to try that though, I would certainly still want something that burns wood. For power outages & maybe some odd supplementing when I felt like it.

Now, if I was in some central places in this continent where -20c is considered a semi-mild spell - that would be entirely different.

 

[Highbeam]

If your stove can heat the whole house from one room then why couldn’t a single head heat pump? I fail to see the difference. Btu are btu right?

I’m sure a lot of things vary from house to house but many folks heat their homes with a single woodstove. I have heard the same odd logic about woodstoves too, just space heaters. Well yeah, the space is your home!

Putt temperatures here in the pnw on average are above freezing but I would not size a heat pump based on that. Instead, use the coldest day. Say 5 degrees that you need to be ready for.

 

[Ashful]

I do want to point out that even though the units may be putting toasty air down to zero that the efficiency is getting close to electric baseboard. IMHO the air movement required to move the air around increases the comfort temperature due to the convective cooling from the breeze. I think folks are far better running radiant baseboard or other alternatives when the temps get down to 10 F or lower but every house will be different. On both my Mitsubishi units, there are three setting for fan speed. Low is quite quiet, far quieter than a window AC unit. Medium is noticeable but not objectionable, high is definitely noticeable and I have to turn up my TV volume to compensate. I find that when I run the unit on high I am mostly trying to get the heat to move around the house farther from the unit. In real cold weather the farther rooms get decidedly colder.

The other thing to keep in mind is these devices do not magically change the laws of physics. If you selected mini splits to meet the design heat load like a furnace there would be several of them lined up next to each other. These are really just fan forced space heaters, great for supplement heat but not so good for a primary heating system.

I do like mine and recommend them to a lot of folks but get worried that some folks listed to the hype and think that they are a viable substitute for a primary heating system in cold climates, they aren't but they sure make a great supplement especially for folks who are now starting to see a need for AC where they used to not need it.

My experience, exactly. I have owned five Mitsubishi mini splits, in three different buildings. I also have a few in my lab at work.

 

[Ashful]

I don't find baseboards take much space away. If you say back a couch up against a wall, the top will hit the wall way before the bottom will hit the baseboard - then just pull it back out an inch or so.

I think he is talking about electric baseboards, which unlike hydronic, can melt your couch or set fire to your book case.

 

[SpaceBus]

I think he is talking about electric baseboards, which unlike hydronic, can melt your couch or set fire to your book case.

I have not found that experience with our 70's Merkel 750 watt electric baseboard heaters. I just keep stuff five inches or so away and that's seems fine. We don't block them for fear of a fire, but so we don't block the heat. I agree that they do force some furniture arrangements when in use. Ours also don't run that much and take over when the stove dies down if we are away or asleep and don't feel like getting up to load the stove. I think we will be getting up tonight to load the stove though. This is the coldest night we've had so far, but we also just got here in November.

 

[Ashful]

I have not found that experience with our 70's Merkel 750 watt electric baseboard heaters. I just keep stuff five inches or so away and that's seems fine. We don't block them for fear of a fire, but so we don't block the heat. I agree that they do force some furniture arrangements when in use. Ours also don't run that much and take over when the stove dies down if we are away or asleep and don't feel like getting up to load the stove. I think we will be getting up tonight to load the stove though. This is the coldest night we've had so far, but we also just got here in November.

I guess it might vary by brand and wattage. My last house had electric baseboard in all five bedrooms, and the upstairs bathroom. More than one of them had melted material on their guards, from where prior owners let synthetic drapes or furniture get too close.

 

[Tegbert]

If your stove can heat the whole house from one room then why couldn’t a single head heat pump? I fail to see the difference. Btu are btu right?

I’m sure a lot of things vary from house to house but many folks heat their homes with a single woodstove. I have heard the same odd logic about woodstoves too, just space heaters. Well yeah, the space is your home!

Putt temperatures here in the pnw on average are above freezing but I would not size a heat pump based on that. Instead, use the coldest day. Say 5 degrees that you need to be ready for.

I guess I should have specified about that more. Yes my insert can keep the house heated. So can my stove. I’ve never tried that with let’s say just my living room baseboards but I am trying it now. My concern is I want the AC. We use a portable ac in the living room a 12,000 btu one and it can’t keep up in the living room. Yes it’s more comfortable than what it would be without it but I want it cooler in there. It definitely doesn’t do much for the bedroom last down the hall either that I have to run a 9000 btu one in the master. That one does seem to keep the master good since I like it cold to sleep but the other rooms across the hall are still too warm. So when an installer says a 12000 btu head will cool the living room and down the hall I have doubts about that. Yeah the mini split one is probably more efficient but how much better does it do than a portable version?


Lopi Rockport
Blaze King Ashford 25

 

[maple1]

I guess I should have specified about that more. Yes my insert can keep the house heated. So can my stove. I’ve never tried that with let’s say just my living room baseboards but I am trying it now. My concern is I want the AC. We use a portable ac in the living room a 12,000 btu one and it can’t keep up in the living room. Yes it’s more comfortable than what it would be without it but I want it cooler in there. It definitely doesn’t do much for the bedroom last down the hall either that I have to run a 9000 btu one in the master. That one does seem to keep the master good since I like it cold to sleep but the other rooms across the hall are still too warm. So when an installer says a 12000 btu head will cool the living room and down the hall I have doubts about that. Yeah the mini split one is probably more efficient but how much better does it do than a portable version?


Lopi Rockport
Blaze King Ashford 25

The split will send the heat (or cold) out further than a stove or radiators. I was surprised how far ours sends it. The fans really distribute the air out & around - much more so than a window shaker if talking a/c. More fan ooomph.

 

[georgepds]

I guess I should have specified about that more. Yes my insert can keep the house heated. So can my stove. I’ve never tried that with let’s say just my living room baseboards but I am trying it now. My concern is I want the AC. We use a portable ac in the living room a 12,000 btu one and it can’t keep up in the living room. Yes it’s more comfortable than what it would be without it but I want it cooler in there. It definitely doesn’t do much for the bedroom last down the hall either that I have to run a 9000 btu one in the master. That one does seem to keep the master good since I like it cold to sleep but the other rooms across the hall are still too warm. So when an installer says a 12000 btu head will cool the living room and down the hall I have doubts about that. Yeah the mini split one is probably more efficient but how much better does it do than a portable version?


Lopi Rockport
Blaze King Ashford 25

By all means, get a manual j calculation to size the equipment


That said, the rule of thumb is 12kbtu/hr for each 600 ft^2. By that rule your AC should be 2x bigger

 

[SpaceBus]

By all means, get a manual j calculation to size the equipment


That said, the rule of thumb is 12kbtu/hr for each 600 ft^2. By that rule your AC should be 2x bigger

Thank you for posting this, I had no idea. When we selected our wood stove I used an online calculator.

 

[Brian26]

Pretty neat how these inverters run. It seems to start out at about 20% output and slowly ramps up to full speed over the course of an hour then quickly goes down. This was on the auto heat setting. I can set it on turbo if I need to and it will run at max capacity.

Here was 2 hours of run time graphed. Outside temp was 25 and it was set to 70.

 

[twd000]

have these technology advances spilled over to the central heat pump units? Are they now able to run efficiently down to single digit temperatures?

I already have central A/C and ductwork. Could I replace my propane furnace with a high efficiency heat pump and come out ahead?

 

[maple1]

have these technology advances spilled over to the central heat pump units? Are they now able to run efficiently down to single digit temperatures?

I already have central A/C and ductwork. Could I replace my propane furnace with a high efficiency heat pump and come out ahead?

I would likely tend to replacing the A/C unit and keeping the propane unit. Yes, there have been advances. You can get a mini-split system that has the indoors part in your ductwork.

 

[twd000]

Replace the outdoor A/C condenser with a heat pump? And leave the indoor air handler and propane furnace for backup? It would be nice to wire the thermostat and control to switch from the heat pump to propane when the outdoor temp gets below ? Degrees

Do you have a link to the indoor units that work with the ductwork?

 

[Tegbert]

Replace the outdoor A/C condenser with a heat pump? And leave the indoor air handler and propane furnace for backup? It would be nice to wire the thermostat and control to switch from the heat pump to propane when the outdoor temp gets below ? Degrees

Do you have a link to the indoor units that work with the ductwork?

My parents have a heat pump hooked to a propane furnace. The heat pump works for them down to 15° or so then switches to propane. It should be relatively easy to switch out as long as the furnace is still in good condition.


Lopi Rockport
Blaze King Ashford 25

 

[twd000]

Yes the furnace is in good shape. Current propane price is about $2.50/gallon. Furnace is 90% AFUE.

How do I estimate cost savings for a heat pump? All-inclusive electric rate is about $0.20/kWh

 

[woodgeek]

HP will usually have higher tonnage (and need bigger ducts and airhandler) than AC for the same space. FYI.