Marc Rosenbaum, P.E., of Energysmiths, in Meriden, N.H., designs and engineers solar, low-energy-use homes.
Q: A customer wants me to install one of the new heat-pump water heaters in the ground-floor utility room of a house built on a slab. I don't have any direct experience with them, but since they work by drawing heat from the surrounding air, won't any energy savings in the winter be at least partly offset by the cost of heating that indoor air to begin with? And could the outflow of cool air from the utility room cause comfort problems?
Q. Same Windows, Different Climates? As a HERS rater working in north-central New England, I've noticed that the U-values of the windows that most builders are installing are quite good — below .35 — but they have low SHGC (solar heat-gain coefficient) values. While it seems that windows with higher SHGC values would be a good idea in cold climates, I've found that most manufacturers offer only low-E windows with these relatively low SHGC values. Why?