Can I improve HVAC efficiency comfort in my home?
My wife and I live by ourselves in a two-story 5600 sq ft home in climate level 5B in Salt Lake City Utah. The top floor is about 2800 sq ft and is at ground level. We live on the east bench of the Wasatch Mountains. The bottom floor of the house abuts the side of the mountain on the east side but on the west side it walks out to a terraced yard.
We have two air-conditioning and heating systems, one for each floor. The more efficient and larger units are for the top floor and frankly, we rarely turn on the heating or air conditioning on the bottom floor because we are rarely down there and because it is naturally cooler down there in the summertime because of the east wall of the bottom floor being nestled into the mountainside and because the top floor AC unit cools off the bottom floor as well.
Our master bedroom measuring 14.5 x 11.5 x 17.5 feet is on the top floor and faces west resulting in our room being one of the warmest in the house during the summer. Because we live by ourselves most of the time except when our kids or friends are visiting, I feel guilty that in order to keep our bedroom cool, we must cool off the entire upper floor. This seems very inefficient. Also, if someone is visiting and staying in one of our other upstairs bedrooms, they seem to be too cold when we set the air conditioner for our comfort level in our bedroom.
Similarly, in the wintertime, turning the heat on to keep our bedroom warm enough for our comfort level also seems inefficient when we are by ourselves as we are heating the entire upper floor. Worse, when we have guests staying on the bottom floor, keeping the bottom floor warm enough for them results in too much heat throughout the upstairs area including our bedroom.
We have lived in this house for approximately 20 years, the last five of which we have had solar panels installed on our house which provide most of the energy for our two electric cars and for the rest of our electrical needs. It produces approximately 12 kW per hour maximum.
I’m thinking that perhaps installing a minisplit heat pump might be the best way to mitigate these temperature problems in our bedroom, hopefully improving our carbon footprint overall. Am I missing anything (we already have ceiling fans in all of our bedrooms and living spaces)? If someone agrees that a minisplit heat pump is the answer, is there a way to determine the correct size of a minisplit heat pump for a room of the size mentioned above? And if so, would this also be somewhat economical- note I didn’t calculate potential savings from installing solar as I felt that I should install it given our city’s air pollution issues and Utah’s dependence on coal for electricity generation.
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