450 sq.ft mini split ductless ?

chipraynor · Jun 4, 2015

Hi, I am looking for some info. I had an hvac tech come out and recommend these items for a small 420 sq ft home. The layout is a bedroom, closet and bathroom (10x16) total 160 sq. where 1 unit would go and a living room/kitchen (1room) (16x16 sq. Ft) total 256 sq. for the other unit. The home is located in Maryland. I’m more concerned about the heat in the winter then I am the AC in the summer. It’s very well insulated. The bedroom and living room also have ceiling fans for circulation.
Does this look like the correct package to go with?

(2) Zone; Lennox 16 SEER High Efficiency Ductless Split Heat Pump System
Lennox 16 SEER; High Efficiency Mini-Split Heat Pump MODEL # MS8-ZO-24P3A
Lennox Mini-Split 9kBTU Indoor Evaporator Unit MODEL # MS8-HI-09P1A
Lennox Mini-Split 18kBTU Indoor Evaporator Unit MODEL # MS8-HI-18P1A
Insulated Refrigerant Line Sets (25' and 50')

My questions is Brand, I personally have a Trane. I see Mitsubishis’ everywhere I go, should I look at a better brand.
Evaporator units? Both areas are very close in size, but BTU’s are double, is that correct?
I’m a builder by trade, I have experience in all plumbing, electric and framing, I’d like to install this myself. Are there any other items I may need.

Thanks for Help,
Chip

Bitters · Jun 4, 2015

WOW, 2 ton's on 429 sq ft? Seems over sized.

chipraynor · Jun 4, 2015

That's what I thought, the whole house is 18x26 and that's an outside measurement.. What do you recommend?

beenthere · Jun 4, 2015

How old is the home?

Hard to believe anyone would recommend a 2 ton or any newer construction home.

chipraynor · Jun 4, 2015

House is redone. New insulation new siding.. New everything but the shiplap. But yes it's old. 1950

Bitters · Jun 4, 2015

I think I would get some else to come out and take a look at it.

user_12345a · Jun 4, 2015

Key is to get a load calc done, then get a variable speed system which can match the load.

Size so that minimum cooling capacity matches design heat gain, and then enjoy the extra heating capacity winter. It may cycle a bit like that in the summer, but you say heating is your to priority.

You should have a second source of heat in case the heatpump fails or can't keep up - be it a fuel burning fireplace or even electric basements.

user_12345a · Jun 5, 2015

electric baseboard heaters, not basements.

MushCreek · Jun 5, 2015

Our house in SC is 1444 square feet, and our winter heat load is 12K BTU, and summer cooling is 9K. We have two Mitsubishi HyperHeat units, but only run one at a time unless it is very cold (near zero). To compare, ours are 30 SEER.

You can buy a Manual J program. I used HVACCalc, about $50 for a 30 day non-professional license. Take the measurements, enter the numbers, and then you'll know. I had a so-called professional try to tell me over the phone what sized system I needed! He was 300% over, which would have cost a lot more to run, and wouldn't have dehumidified enough.

MT Stringer · Jun 5, 2015

I put a Fedders 11K BTU mini split in my garage/woodshop. It works great - 100 deg F outside, 77 inside. I can't help with the cold. Last year we did get some frost, but I had the temp set t 68, and 68 it was (heat pump).

The ceiling has R38 insulation, the outside wall is insulated and the overhead door is insulated and energy efficient.

supers05 · Jun 5, 2015

There's also some free heat calculator sites that are pretty good. They're 100% web-based instead of a download. Most are not completely exhaustive, but come more then close enough. They were within 1 % on my house.

PS. Found some
Very simple:
http://www.loadcalc.net/

Heat Loss only but more options:
http://www.builditsolar.com/References/Calculators/HeatLoss/HeatLoss.htm

Cheers!

450 sq.ft mini split ductless ?

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