# Basement btu estimate



## toadman77 (Dec 16, 2019)

I'm thinking of adding a mini split to my basement.    The location is south west pa.  I have added insulation to my floors (1in foamboard) and 2 inch foamboard on the walls and joists have 2inch foamboard  plus r13 in batts.  The rafters ate also insulated not debated on removing if it's heated.   My guess is  2ft of the walls are above ground.  The windows do need replaced though i put foamboard in them to help for now. 
The temperatures range from 48 when is below 0 to 62 in the summer. The average  is usually in the 50s though.

I'm planning on adding a studded wall  with r13 batts insulation to most of the basement where it is possible. Also replace the old style windows also.  Also  it will be separated into the rooms  but the biggest room id hslf of the basement.

I'm looking into either a 9000 mitsubishi hyper heat or a 12000 fugitsu.  They both modulate  1700/3100  respectively not was wondering what I would possibly need at the coldest times.   Other option though expensive is a mutizone to use a ducted version to the  the bedrooms  and  a  unit in the basement.


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## begreen (Dec 16, 2019)

What are the basement dimensions?


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## DickRussell (Dec 16, 2019)

toadman77 said:


> .....
> I'm planning on adding a studded wall  with r13 batts insulation to most of the basement where it is possible.....



You absolutely do not want to insulate a buried basement wall with a fiberglass batt or any other porous insulation right up against the concrete. That's a recipe for a moldy wall and musty smelling basement. Use rigid foam board, glued on (with PL300 for example) or screwed on with concrete screws & fender washers. with all edges sealed. Over that apply 2x4s on the flat and screwed through, then covered with sheetrock held up off the floor. The sheetrock is for thermal and ignition protection; the 2x4s provide space for shallow electrical boxes. If you wish, the 2x4s (or 2x3s can be installed the normal way and the bays filled with FG batts.

There is plenty of information out there on why you don't want a FG batt against a basement wall, and plenty on how to do it the right way. Here are a couple of  links:








						Adding Insulation to Basement Walls - Fine Homebuilding
					

Learn the dos and don'ts of installing insulation in basement walls. How to choose and install the best insulation for several types of basement walls.




					www.finehomebuilding.com
				











						Best Methods For Insulating Basement Walls
					

The key to successfully insulating basement walls is selecting insulating materials that stop moisture movement and prevent mold growth. Basements are the perfect location for foam type insulation products.




					www.homeconstructionimprovement.com


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## toadman77 (Dec 16, 2019)

The dimensions with a quick guess are 26 ft wide by 38ft.  

I have 2inches of foamboard attached to all the basement walls right now.


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## begreen (Dec 17, 2019)

toadman77 said:


> The dimensions with a quick guess are 26 ft wide by 38ft.
> 
> I have 2inches of foamboard attached to all the basement walls right now.


Sounds like either unit will do the job. The Fujitsu could less expensive and Mitsubishi may produce more heat at 0º. You may find that some resistance heat is more effective for those rare 0º days.


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## toadman77 (Dec 17, 2019)

Thanks. I don't need ac in the summer down there . It's usually in the low 60s.  It should  help keep the humidity down some  and dryer with a smaller unit I'm thinking.  I did find a link and the Mustibushi's H2i 6000 has phenomenal cop ratings  and the H2i 9000 about the same except for  max speed.


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## EbS-P (Dec 18, 2019)

I just did some math.  For 1000$ install cost of a mini split I could run two 1kw space heaters 12 hours a day at 50% duty cycle for forty days a year for *16 years.    *Our climate is so mild I just don’t see how that could pay off for me. Now add in the electricity the heat pump uses it gets longer.
As your heating needs increase I see it as an ok option especially if you need ac.  I really think it’s the best solution if it is the only heating/cooling source for a space and it is certainly convenient.
Evan


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## maple1 (Dec 18, 2019)

EbS-P said:


> I just did some math.  For 1000$ install cost of a mini split I could run two 1kw space heaters 12 hours a day at 50% duty cycle for forty days a year for *16 years.    *Our climate is so mild I just don’t see how that could pay off for me. Now add in the electricity the heat pump uses it gets longer.
> As your heating needs increase I see it as an ok option especially if you need ac.  I really think it’s the best solution if it is the only heating/cooling source for a space and it is certainly convenient.
> Evan



That's only around 40,000 BTUs though, per day Which is just a little bit over what I think my average hourly heat loss is over the winter. (Think mine is 35,000 btu/hr).


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## EbS-P (Dec 18, 2019)

maple1 said:


> That's only around 40,000 BTUs though, per day Which is just a little bit over what I think my average hourly heat loss is over the winter. (Think mine is 35,000 btu/hr).


Which seems about right for a full basement. Like I said it’s pretty mild here.  My water meter is only 6” below ground. I just need to heat a bedroom and an office when it’s being used.


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## maple1 (Dec 18, 2019)

As far as the OP goes, IMO a mini-split would work fairly well. And also give you dehumidifying (well, and AC) in the summer. If you find it won't send the heat as far as you want, like to the other end of the basement, I have had pretty good luck this shoulder season mounting a round Honeywell fan in the upper corner of our kitchen doorway, pointing at the end of our kitchen (away from the heat pump) - the heat pump heat seems to get hung up behind the tops of doorway openings sometimes. I think you might actually find that some of this heat would make its way upstairs also. And make your upstairs floors warmer. Not sure which one of the two would be best, but I would only put in a cold climate model. Even if it is a few $$ more in whatever options you are considering.


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## toadman77 (Dec 18, 2019)

I have a .75 ton and a 1.5 ton to heat the house and use a box fan to circulate air to the bedroom when I'm sleeping  I don't need much ac in the summer and use the 1.5 ton for ac.  The basement would consist of just  heating and run all the time without being around like a space heater would be.


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## begreen (Dec 19, 2019)

toadman77 said:


> I have a .75 ton and a 1.5 ton to heat the house and use a box fan to circulate air to the bedroom when I'm sleeping  I don't need much ac in the summer and use the 1.5 ton for ac.  The basement would consist of just  heating and run all the time without being around like a space heater would be.


An electric space heater can have a timer and thermostat. Try one or two 5000 btu electric heaters down there during a very cold period to see how quickly the space heats up and to what temp.


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## toadman77 (Dec 19, 2019)

I used to of the space heaters last night. In two hours the temperature went up 10 degrees.   It was in the teens outside so I was impressed.  It would be on par with the .75 ton do that sound do the job.


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