Example Plan Change

Here I attempt to detail some simple changes to make a significant improvement in energy efficiency for no extra cost. By paying close attention to the sun one can , at least in this case, reduce heating/cooling costs by 35%

The plan below is a Habitat for Humanity house plan I will use to illustrate the changes.

Above is the standard house plan. With this orientation there is only 1 window on the south west side. There are a number of windows on the north side the side that faces the street. This design only had 12 sqft of glazing on the south side and 36 sqft on the east/west boosting heating in the summer so there will be plenty of additional heat in the afternoon in the summer but little extra "free" heat in the winter.

For each additional 2 sqft of glass on the south side it is like running a 1500W space heater for one hour free of charge in December. For every 3 sqft of glass on the east/west side it is the same as running that same space heater an hour each June evening, just when you want it the least.

At a minimum three things are suggested for a NO COST 18% savings in energy.

1) Move a window from the west & east walls to the south side.

2) Rotate the house about 10 degrees. This would increase winter heating about 10% and reduce

summer heating a similar amount.

3) Reduce overhang.

We now have 36 sqft on the south side and 27sqst on the east/west walls. By moving two windows you reduce the morning sun and more importantly the late afternoon sun in the summer and instead maximize heat gain in the winter during mid-day.

Then by rotating the house about 10 degrees we can get the long side to face due south. With this lot this would not require any extra work or cost. It would also allow the homeowner to take advantage of a great view to the south.

Here is the detail on the overhangs. With the standard 16" overhang the top 15% of the window would be shaded in December. Since reducing the overhang actually will decrease the cost of the house a little this is an easy change to make and to sell.

With the overhang reduced on a standard window we now have full sun in December but as you can see full shade in June. Just what you want on a solar house.

Then if we did a mirror image of the house then we can place a second bedroom window on the south side and we can have the larger picture window in the living room facing south. Now we have 68sqft of glass on the south side. Again I would personally prefer to look out at the view than the street from the large window. By placing more window area on the south side the savings increases to 35%. This improvement was done with NO additional cost.

The USA just changed Daylight Savings Time sooner this year to help on the premise to cut energy consumption an estimated 1%. By educating the public and contractors we would easily exceed that savings many times over.

If you wanted to approach 50% you would need to place larger windows on the south side and add say tile floors to store some of the noon time heat for the evening. That would however add some to the cost. But is is fun and rewarding to see how far one can go.