Slashdot Mirror
Controlling Heating/Cooling on a Complex Schedule?
Controlio asks: "I've just replaced my furnace, air conditioner, and humidifier last week, in a house that I am rebuilding almost completely from the studs. With the outrageous cost of heating oil, I looked at saving some money by installing a programmable thermostat. However, my work schedule is too complex for most programmable thermostats. The one benefit I have is knowing my schedule a month or two in advance. So, the most practical option seems to have some sort of computer-controlled system that can accept calendar-based setpoints. This would also allow me the opportunity to VNC to the computer from work and change the schedule, in case of last-minute scheduling changes. The ideal solution would be able to control the heat and air conditioner, plus have the ability to do humidity setpoints (though it's not required). Also a system that could control two furnaces would be beneficial, since I plan on installing a heater in my garage this year. Does anyone know any hardware and software combination available to accomplish this?"
plus have the ability to do humidity setpoints (though it's not required)
Oh, one last thing. Your relative humidity setting should be a constant function of the outside temperature. Why? Otherwise you risk condensation, and condensation leads to rot and mold. Of course, if your house is insulated properly, a whole house humidifier built into your ducts will never get the humidity up to your requested setting before the furnace shuts off, but that's a whole different problem...
In the spirit of what people idealize /. to be, I present the URL to an opensource project called DIY Zoning (that is, Do-It-Yourself for those who live in an apartment). It is a very well designed website with links to best practices and pointers to basic parts and the sourceforge-based software. From the site:
If you're replacing the furnace and tearing the house apart as much as you say, why not switch to electric or radiant heating? The difference between the cost of electricity and heating oil will lower your heating costs more than a computer-controlled thermostate ever would.
Absolutely, 100% totally, completely incorrect.
Electricity costs more per BTU than oil, period. This is because electricity is, quite frequently, made from oil, gas and coal, usually at a 30-35% efficiency, never at better than 50% efficiency. Then there are the logistics issues of delivering the ultimate perishable good, invariably losing some of it on the way. All of these contribute to its cost. You WILL pay more per BTU for electricity than for any fuel.
A good, high-quality oil or gas furnace will start at 90% efficient and work up from there.
As for suggesting radiant heat as an alternative to oil, that is the same logical fallacy as suggesting a car instead of a Subaru. Radiant heat uses electricity, oil, gas, coal, or whatever else fuels your boiler.
www.wavefront-av.com