
Renovating or re-modeling:
Two 2" x 4" stud frames separated by a 2" x 12" top plate as in the picture, filled with R19 insulation from both sides will give about an R40 wall. WIth an R40 ceiling and similar care taken with the floor, heating and cooling energy needs for this space will be minimal. Extra work and money up front, you ask, of course, but then negligible energy bills forever, it's worth it. You can reduce to a 2" x 8" wall if using a sprayed expanding foam product to give the same advantage and an even more air-tight wall.
- Are you thinking of renovating or re-modeling? This is an ideal time to become more sustainable
- If you're going to build a new structure consider 12 inch walls, the two by four is not Sustain-Age thinking
- If you're renovating and could lose a few inches in the room, consider adding insulating panel to the walls
- Orientate your new structure to the south and take advantage of solar gain
- Consider the quality, size and design of things like windows, doors and lighting
- In short design your new space to serve you and sustainability
Two 2" x 4" stud frames separated by a 2" x 12" top plate as in the picture, filled with R19 insulation from both sides will give about an R40 wall. WIth an R40 ceiling and similar care taken with the floor, heating and cooling energy needs for this space will be minimal. Extra work and money up front, you ask, of course, but then negligible energy bills forever, it's worth it. You can reduce to a 2" x 8" wall if using a sprayed expanding foam product to give the same advantage and an even more air-tight wall.

Insulated panel:
If you're renovating and can't open up the walls, but can bare to lose a few inches in the room, consider adding insulated panel to the walls with sheet rock glued to them. You can gain R5 insulation values for each inch of paneling added. On many older stone-walled homes in Pennsylvania there is little or no insulation between the plaster wall and the exterior wall. This is a way to add insulation, but of course moldings, etc., have to be removed, so only if you're renovating anyway.
A one inch sheet can also be used inside closets where mold may form due to the coldness of the exterior facing wall. Because the closet door is closed, it is colder inside and condensation forms on the wall to feed the mold.
For new construction there are SIPs (Structurally Insulated Panels) that can be used.
If you're renovating and can't open up the walls, but can bare to lose a few inches in the room, consider adding insulated panel to the walls with sheet rock glued to them. You can gain R5 insulation values for each inch of paneling added. On many older stone-walled homes in Pennsylvania there is little or no insulation between the plaster wall and the exterior wall. This is a way to add insulation, but of course moldings, etc., have to be removed, so only if you're renovating anyway.
A one inch sheet can also be used inside closets where mold may form due to the coldness of the exterior facing wall. Because the closet door is closed, it is colder inside and condensation forms on the wall to feed the mold.
For new construction there are SIPs (Structurally Insulated Panels) that can be used.

Solar gain:
Orientate your new structure to the south and take advantage of solar gain. Or if you already have a south facing porch, like the one in the picture, you can glass it in to take advantage of the solar gain in winter.
Although the sun runs from east to west in summer and winter, it makes a much lower run in winter, getting in under eaves and into windows where the solar gain can be used for home heating. The porch above goes to 80º - 90ºF in winter and a fan connected to a thermostat pulls the air into the living space for much of the day. (See a video of this here). The ceiling and floor were insulated when it became an interior porch and windows are opened in summer, keeping the porch cool.
Take control:
The bottom line is, in the Sustain-Age, we have to be engaged citizens. Our decisions cannot be passive, but informed by our sustainable awareness. Because even the builder, who you may contract for a renovation, may not be sustain aware yet. This may mean that you have to explain your principles of design to them. This will usually be decided at the architect stage. Even if the walls are fantastically insulated, it won't matter if doors and windows leak. So the whole package must be considered.
A renovation is a good time to consider a 'safe room' in your house. Which room needs the least energy to keep warm if there were an energy crises during the winter? The new renovation, using some of the ideas above, could become that space.
Orientate your new structure to the south and take advantage of solar gain. Or if you already have a south facing porch, like the one in the picture, you can glass it in to take advantage of the solar gain in winter.
Although the sun runs from east to west in summer and winter, it makes a much lower run in winter, getting in under eaves and into windows where the solar gain can be used for home heating. The porch above goes to 80º - 90ºF in winter and a fan connected to a thermostat pulls the air into the living space for much of the day. (See a video of this here). The ceiling and floor were insulated when it became an interior porch and windows are opened in summer, keeping the porch cool.
Take control:
The bottom line is, in the Sustain-Age, we have to be engaged citizens. Our decisions cannot be passive, but informed by our sustainable awareness. Because even the builder, who you may contract for a renovation, may not be sustain aware yet. This may mean that you have to explain your principles of design to them. This will usually be decided at the architect stage. Even if the walls are fantastically insulated, it won't matter if doors and windows leak. So the whole package must be considered.
A renovation is a good time to consider a 'safe room' in your house. Which room needs the least energy to keep warm if there were an energy crises during the winter? The new renovation, using some of the ideas above, could become that space.