Thursday, October 16, 2008

Living Room Temperatures in the Winter

A "neighbor" of mine shared his experience and send me this question:

"Winter is the time for talking about what is to be done next summer. What temp do you keep that house at during the winter ? I burn five to seven cords of wood, mostly elms that died the last summer, each winter. Stays 60F to 65F in the house."

Here's my reply:

My ultimate goal is to achieve 74+ °F all winter long while I'm in the house...and even just with passive solar and my masonry stove I frequently got the house back up to 72°. On cloudy, cold days the temperature might drop to 62 or 63 by 6 PM but by 8 PM it's back up in the upper 60s or lower 70s--with only one fire (using about 12-15 "smallish" logs). On weekends it's usually quite feasible to have the whole house warm (i.e., in the 70s) the whole weekend with four or five fires between Friday evening and Sunday evening. Overall I'm estimating that I used about four to five face cords or about two full cords per winter.

This winter, things will hopefully be even better. With help from friends I just installed my solar hot water collectors up on the roof (still need to do some leakage testing) and with that I'm ready to continue installation of my solar hot water and masonry stove heated radiant in-floor heating system. Which means that I will bring about 860 sq. ft. of 4" concrete up to a comfortable temperature (i.e., 72-75 surface temperature for a 65-67° "head-level" temperature). So I will have almost 300 cu ft. of concrete heated up - a lot of thermal mass that will be difficult to cool down once it's heated up.

Monday, October 13, 2008

Fridges and Refrigerators

Having heard about "A++" appliances (a program comparable to the Energy Star), out of curiosity I looked for energy-efficient fridges that are being sold in Germany.

One model that I found just after a few minutes of searching is a bottom-freezer fridge with about 12 cu ft of usable capacity (did you know that a fridge sold in the US as an "18 cu ft" fridge only has about 13 to 14 cu ft of usable space (source: Consumer Reports)?). Whereas a typical energy-efficient top freezer uses at least 370 kWh per year (that's what my fridge uses), this fridge uses only 211 kWh a year.

(For all those "off-gridders" out there - the Sunfrost RF19 (which has a little less usable capacity than 12 cu ft) uses about 300 kWh a year - at a cost of $2,700+...)


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