Mini Split Sizing for cooling and heating
I’m new here. I am in the process of planning renovations for a newly acquired home. It’s unbelievable how many times I ended up on this site in my quest for information regarding energy efficiency and general best practices, so I thought I should finally join.
As part of the renovations we are planning on installing a mini split heat pump. The primary reason for installing the unit is for conditioning during the summer months; obviously the house already has a heating system (electrical baseboards) but no ac.
That being said, I am very much aware of the much greater efficiency of a heat pump vs resistance heating, and so if I will be installing one I would want to use it for heating as well as much as possible.
The house is near Montreal, so definitely a lot of cooling in the summer and a lot of heating in the winter. Cool Calc assumes the following design temps:
Summer Indoor Design Temperature: 73F
Summer Outdoor Design Temperature: 83F
Winter Indoor Design Temperature: 70F
Winter Outdoor Design Temperature: -7F
Here are the house specs (see attachment for a 3D pdf plan of the top floor).
-Built in 1987
-One floor and basement
-Main floor is open concept and has 2 bedrooms. Total area approx 900 sqft.
-8 ft ceiling
-Main floor windows to be replaced as part of renovations
So far, every single contractor I’ve talked to is proposing a 12000 BTU unit. However, some say that I will be able to use the unit for the majority of my heating while others straight out say there is no way and I will still have to mostly rely on resistance heating.
My top contenders right now are the Fujitsu 12RLFW1 and 12RLS3.
Your comments would be very much appreciated.
PS: By the way, manual J calculations seem to never be done around here, or at least not for project this small/simple. I did attempt to get a rough estimate using Cool Calc, but I am not confident in my input and therefore in the results.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part