Ducted Mitsubishi Mini Split in encapsulated crawlspace update: Geothermal installed!
We’re thinking of putting a 36,000 btu Mitsubishi ducted mini split in our encapsulated crawlspace. It is about 5 feet high and approximately 490 sq ft. Are we creating a problem? Of course the condenser unit will be outside. Our attic is out of the question because it is not a conditioned space. We live in the Hudson Valley where the temps in winter can go down 5 degrees Fahrenheit.
Update:
After much consideration decided Geothermal was a much simpler and more environmentally sound solution. The Minisplit System required 6 heads and 2 outdoor units and the holes in the house walls for the refrigerant and drain lines but the big factor was the ongoing maintenance! The other really bothersome thought was all that equipment and plastic ending up in a landfill in the future. After installing the Geothermal we end up with a vertical loop and a heat pump in the basement. We will also have to replace the existing 35 year old ductboard duct system with a new 3 zone metal duct system. Quotes for that have been in the $7000 to $12000 range. Does this sound about right for a 1900 sq ft house? The MiniSplit System was quoted at $17,555 and the Geothermal $21,315 both quotes are after all rebates and tax credits have been applied.
Update: Dandelion finished the installation of our Geothermal System! The process started that started in late April has been completed as of September 15th (I extended the time by some 5 weeks because of guests visiting in the summer). Gone is the oil furnace and tank as is the air source heat pump. The cost came in right on target at $21,315. In our case the electrical and ductwork had to be upgraded which added to the costs. The final total for the conversion is about $35,000. We now have a 5 ton Geothermal System which required two wells 288ft deep to be drilled. Winter will tell if we have made a wise decision but the cooling is phenomenal! I would definitely recommend Dandelion Energy if you are in the Northeast for a Geothermal Installation.
Replies
Do you have access to the space which will allow installation and service?
Management of condensate needs to be considered, including expected temperature extremes in the crawl space.
Access is no problem and the space stays between 55-70 degrees depending on the season year round. It is below grade with poured concrete walls.
a few more things to consider:
Ducting runs (of course) Supply and return.
wiring.
drains for the condensate
and for a safety pan you put under to help if/when the condensate drain gets clogged with gunk
Is there a drain/sewer line you can get to to use for the condensate? a floor drain would be ideal, but if there is a waste line you can modify it would work as well. Would want to think carefully, and imagine a waste line clogging up. there are some ways a sewer can clog up when you might not want an opening in that crawl space.
I would agree on the condensation factor. let me tell you a story about a closed, encapsulated crawl space done quite differently. In the 1980s there were a number of houses constructed with a 'PlenWood Heating System." It was a sealed crawl space, no vents; heating system consists of heat pump and air handler. There is no duct work, only an empty crawl about 1855 square feet by 48" . I have not been in it but can look and see that it is about that deep (we did not build the house). Apparently, it is not difficult to work in, as no plumber has ever complained. There is also a large masonry (Russian Fireplace with 3 flues) that is used in colder months, I do November thru March, Olympic Peninsula, Washington State. Average winter temp maybe 40 degrees, but known to drop to the upper 20s, little snow, but lots and lots of cold, wet rain. Floor registers distributed as usual in this climate. Other than plumbing, sewer etc. and piping for air to the Russian fireplace, it is empty. It works well, indoor temps can be what is wanted, we usually are about 69/70 degrees. This area is completely insulated on the perimeter, no insulation in the floor; crawl area is encapsulated with whatever plastic used in a crawl space. The air handler fan is set to run constantly, summer and winter. We've lived here almost six years and only used the AC for a couple of weeks on summer - lots of trees. The cement and brick 'stove' also provides heat to the crawl space in winter. System was 30 years old when we purchased, never altered. We replace the air handler and heat pump the first year, considered have it ducted, but decided to go with what had worked, and have not been sorry. The heating contractor who had installed the original unit, stated we could go either way and it would work. This type of heating system is no longer permitted, but I have been told that the general way it works can still be used, based on new informaton. Here is a link that explains it. http://diy.vooxo.net/crawlspace-strategy-the-plenwood-system/
Bit puzzled by not being able to put the unit in the attic. not being conditioned. These split units are being used in our climate and are always outside as are the big heat pumps. I am only a homeowner, not a heat expert, but can figure out how things work. We had a previous home that had no closet for gas furnace, nor was there room in the crawl for ducts. We put it in an unheated attic space with downdraft registers -- again it worked very well. Your space and temps seem it would work well.
Our attic is inconvenient to access as well as being extremely hot (not good for computer controller boards) and cold depending on the season. Servicing the ducted unit becomes so much easier in the crawlspace.
things to consider:
ucting runs (of course) Supply and return.
wiring.
drains for the condensate
and for a safety pan you put under to help if/when the condensate drain gets clogged with gunk
and Do you have access to the space which will allow installation and service?
Management of condensate needs to be considered, including expected temperature extremes in the crawl space.
Not sure if I should feel complimented or annoyed.
Perhaps he/she wanted to comment on my post and got distracted.
Sorry but was replying to both yourself and 1whitbred.
I can't imagine what the problem would be. Nowadays AC ductworks is supposed to be in the conditioned space.
how much per month in winter is your electric/utility bill?
From Oct 2020 thru Feb 2021 averaged $172.54 per month at a rate of .17 per Kwh
Have an air source heat pump which heats down to 35 degrees then the oil furnace heats the house.