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Unfortunately labor and parts markup is high. An equivalent SEER system installed was quoted to me at around 15k. I probably spent 5k between the system and misc parts and tools.
 
The Mr. Cool mini-split has completely stopped producing heat. Everything runs, but the fan won't go above the lowest setting except in Fan mode, and there is zero heat. It's as if it's below Zero outside, but it does this even above 32F. There are no trouble codes displayed. I see on the Interweb that this means it's low on refrigerant, and there is a guy selling kits that let you top the system off with the appropriate refrigerant, containing stop-leak. On the one hand, the symptoms match well. On the other hand, this (it seeming to die) happened when I mistakenly hit the Sleep button several times, thinking it was the Fan button. Is there any chance that it's related to that, or should I be checking the refrigerant level? $200 for the kit seams reasonable...

https://computrader.myshopify.com/p...charge-kit-plus-uv-dye-sealant-all-in-one-fix
 
Have you tried power-cycling the unit? It is very suspicious that the problem happened after you hit the 'wrong' button a few times.

In general, I avoid stop-leak type products like COVID. Much better to add some UV dye to the system, find and fix the leak than to put some non-OEM gunk inside. Just my $0.02.
 
Oh yes, I've power cycled it, for times ranging from 1 minute to 10 hours. Nada. I get your point on the dye, but this kind of installation is 90% inaccessible once finished, I'm afraid. I'm thinking I'll get the kit (plus a UV flashlight he has on sale, or a similar one), and see what the system pressure reads. Another point that concerns me, though, is that the unit has to be running in A/C mode, with a line temp of something like 210F. Can I get that line temp in Winter, with possible low refrigerant? I haven't tried contacting Mr. Cool yet, but I'm seeing comments saying that they aren't returning calls or emails.
 
Leftie, sorry I'm late to the conversation -- I've been off MNL for a while, focusing on green energy projects at home. If it's not too late -- or if the Mr. Cool equipment needs to be replaced anyway -- could you swap the entire unit out for either a Mitsubishi or Fujitsu wall unit? The equipment on those units is priced comparably to a Mr. Cool, but they have much better low temp performance, supposedly better reliability, longer warranties in most cases, and most importantly, much higher COPs at all the relevant winter temps (47, 17, 5, -5, etc).

You mentioned further up in the thread that the local installer charged outrageous prices for either Mitsubishi or Fujitsu equipment. That's been my experience too down by NYC (and I think it's true most places these days), but I eventually found a small (1-2 people) local HVAC shop that installs Fujitsu hyper heat units for $3,500 per unit total installed cost. That's not too bad when you figure the equipment itself (evaporator, condenser, line set kit, etc) costs around $2,000 - $2,500 per unit online. It took me a year to find them -- everyone else around here wanted $6,000 - $8,000 per unit, and they all tried to talk me into oversizing the units, putting a wall unit in every single room, putting duct work and air handlers in our unconditioned attic, etc. But I now have two Fujitsu hyper heat wall units -- one 9k btu and one 15k btu -- in our two-story 1500 sq ft house (total installed cost was about $7,000). The 15K unit, which is in our dining room, basically heats the whole house by itself, with a minor assist from the 9K unit. We've all but stopped using our gas boiler. I'm not sure which Mr. Cool unit you have - I came very close to going with those myself. But after considering their winter COP data, and considering that even with the DIY Mr. Cool unit, I'd still have to hire an electrician to wire it and still have to hire an HVAC company to purge the line sets, the Fujitsu units actually cost less in the long run.

Here are the specs on the 15K Fujitsu unit that we have. The most important info for me is COP at 47 F, since the average temp in my area during the September - May heating season is 46 F. For Mr. Cools, I believe the COP is around 3ish at 47F, whereas with the Fujitsu units it's at around 5. I did a Manual J on our house and based on a whole house heat load at 47F of around 11,000 btu/h, the average COP of this unit is around 5.5. We're on track to use only 3,000 - 3,500 kwh to heat the house during that nine month season. Our 99% outside design temp is 11F. The attic is insulated to R-49, the basement walls and rim joist to R-10, but there is no insulation in the walls and the house is extremely leaky (100 years old, CFM is still at around 3600 after some piss poor air sealing).

https://ashp.neep.org/#!/product/51107
 
Also, you may already be aware of Green Building Advisor, but the folks on those forums are very knowledgeable and generous with their time:

https://www.greenbuildingadvisor.com/
 
Update: after being essentially dead for a few weeks, the unit came back to life, over the span of a day or so, and is now working ok again. Neither I nor the tech I was consulting with knows why.

If this unit dies before June, I will get a new one. If it happens after that, I probably will get a better one. I do know that I can no longer install anything like that myself. I'd probably go with one high performance outdoor unit like the Hyper Heat, and two or three room units.

But after considering their winter COP data, and considering that even with the DIY Mr. Cool unit, I'd still have to hire an electrician to wire it and still have to hire an HVAC company to purge the line sets, the Fujitsu units actually cost less in the long run.

The DIY unit does not need to be purged. It is already purged and pressurized. I was able to do the wiring myself.
 
Kieran973 said:
I did a Manual J on our house and based on a whole house heat load at 47F of around 11,000 btu/h, the average COP of this unit is around 5.5. We're on track to use only 3,000 - 3,500 kwh to heat the house during that nine month season. Our 99% outside design temp is 11F.

Did you use some sort of software package for the Manual J calculations or did you just do it by hand? I'm just getting started on planning my new HVAC and I'm wondering if this is something I can handle myself or if I should contract it out to a pro.
 
LeftieBiker said:
Update: after being essentially dead for a few weeks, the unit came back to life, over the span of a day or so, and is now working ok again. Neither I nor the tech I was consulting with knows why.

If this unit dies before June, I will get a new one. If it happens after that, I probably will get a better one. I do know that I can no longer install anything like that myself. I'd probably go with one high performance outdoor unit like the Hyper Heat, and two or three room units.

But after considering their winter COP data, and considering that even with the DIY Mr. Cool unit, I'd still have to hire an electrician to wire it and still have to hire an HVAC company to purge the line sets, the Fujitsu units actually cost less in the long run.

The DIY unit does not need to be purged. It is already purged and pressurized. I was able to do the wiring myself.

Glad to hear it's working again. You're right about the DIY units - I was thinking of their other ones.
 
goldbrick said:
Kieran973 said:
I did a Manual J on our house and based on a whole house heat load at 47F of around 11,000 btu/h, the average COP of this unit is around 5.5. We're on track to use only 3,000 - 3,500 kwh to heat the house during that nine month season. Our 99% outside design temp is 11F.

Did you use some sort of software package for the Manual J calculations or did you just do it by hand? I'm just getting started on planning my new HVAC and I'm wondering if this is something I can handle myself or if I should contract it out to a pro.

I used Cool Calc for the Manual J:

https://www.coolcalc.com/

I found it easy to use, and I'm not at all a STEM person. Doing your own Manual J is time consuming however - gathering measurements of every room in your place, making sure the data you enter about insulation, air infiltration, and window U-values are correct, etc. That being said, I couldn't actually find a local pro to do a Manual J, so I had no alternative - every hvac company I asked said they don't do that. And it certainly showed in their proposals: most of the local companies proposed systems that were obscenely oversized based on the actual heating load. Our heating load for a 99% outdoor design temp of 11F is around 30,000 btu/h, but most of the "elite" and "diamond" Fujitsu and Mitsubishi contractors were trying to sell me on 48,000 - 70,000 btu/h systems.
 
And it certainly showed in their proposals: most of the local companies proposed systems that were obscenely oversized based on the actual heating load. Our heating load for a 99% outdoor design temp of 11F is around 30,000 btu/h, but most of the "elite" and "diamond" Fujitsu and Mitsubishi contractors were trying to sell me on 48,000 - 70,000 btu/h systems.

Agree with this- it is time-consuming but productive to do your own heat loss calculations because it is my suspicion that contractors do a quick run-through and then multiply by about 2 to be sure. So do your own, carefully, and stick with it, adding maybe 20%.....
 
It looks like our central A/C unit is dying. It and the furnace are both over 20 years old, IIRC, so I'm reluctant to throw money at it. Can anyone point me to a good, honest, reasonably priced heat pump installer in the Albany - Saratoga Springs NY area? I've been trying to talk my housemate into getting a good air source heat pump that will provide enough heat down to 0F or so. It would probably have to have a backup furnace for her peace of mind, and that furnace would have to be either electric or oil -she's terrified of gas. I'm willing to put in $5k, so it would have to be in the $15k range, installed. I am no longer able to do this kind of work.
 
Update: the issue isn't, as I at first thought, a refrigerant leak. For some reason the outdoor A/C unit tripped its breaker, leaving the system blowing cool air just because the ducts pass through our chilly cellar. I reset the breaker, and now it's running more or less normally, blowing cold air. This is the first time, though, that it's done that, so I'm guessing it won't be the last.
 
I've been trying to talk my housemate into getting a good air source heat pump that will provide enough heat down to 0F or so. It would probably have to have a backup furnace for her peace of mind,

We run heat pumps in one rental unit which have reliably heated with no backup for 3 years in Vermont- it is a Fujitsu unit but others are probably by now able to provide heat at well below zero. I know this does not ease the "peace of mind" issue but..... it can work!
 
dmacarthur said:
And it certainly showed in their proposals: most of the local companies proposed systems that were obscenely oversized based on the actual heating load. Our heating load for a 99% outdoor design temp of 11F is around 30,000 btu/h, but most of the "elite" and "diamond" Fujitsu and Mitsubishi contractors were trying to sell me on 48,000 - 70,000 btu/h systems.

Agree with this- it is time-consuming but productive to do your own heat loss calculations because it is my suspicion that contractors do a quick run-through and then multiply by about 2 to be sure. So do your own, carefully, and stick with it, adding maybe 20%.....

The story I've heard is that installers have two big reasons to oversize:

1. Bigger installs mean more profit
2. It would be a rare post-installation call complaining of poor efficiency (and it would be easy to deflect the blame) but woe to the installer who gets a call complaining that the system is inadequate to keep the house at the desired temperature. Merkins are their own worst enemy.
 
We run heat pumps in one rental unit which have reliably heated with no backup for 3 years in Vermont- it is a Fujitsu unit but others are probably by now able to provide heat at well below zero. I know this does not ease the "peace of mind" issue but..... it can work!

Thanks. It isn't as if we couldn't run electric space heaters if needed - we do that now. If I can succeed in convincing her to delete the fossil fuel furnace, then we can probably afford a good heating system. The issue then becomes mating an air source heat pump with our hot air duct work. Or going back to trying to find a contractor who will install a heat pump in tandem with our existing oil furnace...
 
I didn't see any other mention of solar heating except for opening shades. We have what we call a solar green house and two Sunmate solar heating panels. Together they supply between 30% and 50% of our heating. We also have insulated shades on most of our windows that more than double the R-value of double pane windows. By the way we also have photo voltaic panels on our roof (installed after the heating panels). They supply enough electricity to cover all of our electrical usage including for our Nisan Leaf.

Here are two links to what we have.

http://photosbybmw.com/Tutorial_pages/solar_heat.html

http://photosbybmw.com/Tutorial_pages/window_insulation.html
 
Put in a whole house fan last night. I completely removed the AC last fall in anticipation of getting some sort of heat pump system but that project could be a year or two out so hopefully the fan will work in the meantime.

We always open the windows at night since the temp here in CO cools off nicely nearly all the time at night. The exception would be if it is cloudy but in the summer, clouds usually mean rain or a cold front has just passed through.

I put in a QuietCool ES-4700. It is on the large side for our sq.ft. but I read that running a larger fan on a lower setting is better than vice versa. I didn't bother putting in a timer and just ran the fan on low for about 6 hours. It's quiet and I'd say it's about as noticeable as having a dishwasher running in the distance. Ie, if you listen for it you can detect it but it probably won't keep you awake.

I installed it myself and the hardest parts were maneuvering around the attic with the blown-in insulation and trying to figure out the incredibly poor wiring instructions.

I also had to install 4 new gable vents to provide adequate exhaust flow but that was pretty straightforward. In fact, just doing that probably helped quite a bit since as soon as they were in I could feel the super-heated air from the attic flowing through them. I do have roof vents and some soffit vents but the the total equivalent vent area of those is probably just a few square feet.
 
I just ordered 8 more (325W) panels today since Unbound Solar had a 'garage sale'. That should add about 40% to my existing array. I'll have to increase my usage before my utility will let me install them.

The overall cost/watt will be much lower this time since a lot of the infrastructure is already in place and I know what is needed so I don't have to buy a 'kit' but can shop around for the best prices on the various components.
 
LeftieBiker said:
It looks like our central A/C unit is dying. It and the furnace are both over 20 years old, IIRC, so I'm reluctant to throw money at it. Can anyone point me to a good, honest, reasonably priced heat pump installer in the Albany - Saratoga Springs NY area? I've been trying to talk my housemate into getting a good air source heat pump that will provide enough heat down to 0F or so. It would probably have to have a backup furnace for her peace of mind, and that furnace would have to be either electric or oil -she's terrified of gas. I'm willing to put in $5k, so it would have to be in the $15k range, installed. I am no longer able to do this kind of work.

The improvement in efficiency is huge if you replace your heat pump with Maytag. I've been told that the installation process is more important than the actual brand.
You will get a better answer with an idea of the current ground source heat pump, air source heat pump, heating/cooling capacity, and your Building Science Climate zone at this attached site.
 
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