Written by Nan Fischer
Once the infrastructure decisions were finalized, Alex, the construction contractor, and I could firm up our plans. We knew where water and gas lines could go in the house and greenhouse.
Not only did I plan on the greenhouse addition, but I also made some drastic changes in the rest of the house.
1) I replaced all my single pane windows and sliding glass door with vinyl, double pane, energy efficient, low-e windows.
It’s important to choose the right windows for different areas of a home. Lighting, vies and orientation are taken into consideration.
There are several criteria to determine a window’s performance, two of which are:
- Solar Heat Gain Coefficient (SHGC) – the higher the number, the more heat the window transmits.
- U-factor rating of the National Fenestration Rating Council (NFRC) – the lower the number, the more efficient the window, based on the glass, frame and spacer material.
I have big pictures windows and a slider on the northeast side facing the mountains. Sun pours in here on summer mornings, so I chose windows with a low SHGC that let in sun and but heat. Obviously, on the southwest side, that’s not what I wanted, so I chose windows with a high SHGC that allowed the sun to heat the space.
Low-e stands for low-emissivity. There is an invisible, thin coating on the glass that controls the amount of heat moving through it and affects the SHGC and the U-factor. All windows should be labeled with this information.
2) I changed the floor plan in western 2/3 of the house to facilitate heating, which was difficult due to a remodel done by a previous owner. The traffic flow was choppy, which also prevented heat from being distributed evenly. I was spot-heating separate areas, which was a continual experiment and not very effective. If I could easily get the rooms heated, I would further reduce my energy bills.
3) I created two separate heating zones:
- The greenhouse, girls bedrooms, a bathroom
- The kitchen/living room, my room, a bathroom
Do you remember that huge room where I installed that huge sunny window previously? I split it in two and gave the girls identical rooms. The doors, which I recycled from other parts of the house, opened into the greenhouse, which would help heat them and the second bathroom. This area was separated from the kitchen/living area by a steel exterior door.
4) I added insulation in the ceiling over the kitchen/living part of the house. Since we put gas lines in the attic and access panels in the ceiling, we got a chance to look at the insulation. It was pretty thin, and we had disturbed a lot of it with our work. I decided to beef it up by having R30 shredded fiberglass blown in on top of what we guessed to be about R19 insulation. I was eager to see how my heating bills would react.
My original thought for the greenhouse was to create a 5.5′ wide passive solar hallway to the girls’ new rooms and bathroom. This would span the entire front of the space. After many measurements and number crunching, we decided to fill the entire corner with the greenhouse. It would be easier for Alex to build if we brought the exterior wall out even with the existing wall. This space was 8.5′ wide and allowed the planting bed to be included.
Once we had these dimensions, we could create a detailed design and start ordering materials.
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