Heating and Cooling Load Differences
I recently ran a full manual J using Rhvac software on my new house design and am questioning the numbers.
The house will be located in Maine (zone 6A) and face west, which I know isn’t ideal but there are some spectacular mountain views that are worth it. The overall heating load came in at 37,885 btu and cooling load at 81,588 btu.
The cooling load is largely driven by the 840 square foot great room which has a cooling load of 36,685 btu and a heating load of 6,845 btu. The walls will be a R27 urethane SIP and roof a R55 EPS SIP. There will be 240 square feet of westerly facing triple pane windows and 112 square feet of southerly facing triple pane windows both with an SHGC of 0.54.
It looks like the Great Room cooling load is driven by the window area, but I’m questioning if a 36k btu cooling load really makes sense for an 840 square foot area?
I also took a look at an R27 SIP versus an R41 SIP wall and the heating load difference was only 700 btu. Given this, is there any reason to upgrade to the R41 SIP wall?
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