I’m not sure if these have been asked and answered, my apologies for repeats.
When cooling a house, what is the most efficient way to cool the upstairs? My house is surprisingly pleasant at 77 F during the summer, however, it’s uncomfortable to sleep at night. I think running a fan would be ok, but I’d rather try to blow more air through my one vent in the master bedroom. Is there an easy to do this?
Also, I believe I read here that keeping the house somewhat cool say 77 F during the day when I’m not home is more efficient than having the air conditioning off (for example, it heats up to 83 F), and trying to cool the house to 72 F.
Is the same true for heating a house? Is it also true for a water heater?
For the water heater, I was thinking of putting the water heater on “Vacation” when I’m not home or using hot water. But, when I go and take a shower and shave in the morning, do laundry or run the dishwasher (not all at the same time), I’ll then turn up the water heater to “hot.” Is it more efficient to keep it at “Warm” the entire time?
I’m not sure if this is “easy” but a whole house fan is an efficient way to cool a house down at night. It blows a high volume of air out of the house, usually through the roof, and draws in a high volume of cool night air, which will cool the house down quickly, and with less energy than an air conditioner.
I think this is entirely false. From the standpoint of strict energy efficiency, it’s more efficient to let the house heat up, then turn the AC on in the evening. However, where this fails is in terms of comfort, you’re sitting in a hot house waiting for the AC to bring temperatures down.
Similarly, with your water heater, you will get energy efficiency by turning it off, or way down, when not using hot water, but when you want hot water, you have to wait for it, or do without.
Some of your questions have been answered many times.
With respect to the setback temperature, AFAIK it will always save money to turn the system off (within reason) when you are not at home. This is due to the gradient of heat transfer being very strongly impacted by the differential temperatures (and the fact that most people have a hard time conceptualizing the constant heat transfer loss of their home). The validity of this has been proven by myself and others on this Board with calculations and cites. A possible compounding factor is maintaining the relative humidity of the house, which could suffer in some situations (or could raise the humidity in the house to a point where you really don’t want it). I would suspect that for most well-sealed houses the humidity aspect does not significantly impact things, but that is only IMO.
For a water heater you will save the most energy by keeping it off as long as possible. I cannot think of a case where cycling the temperature would be bad, except if cyclic stress was a concern for the structure of the tank. And to be honest, if that little of stress makes a difference, it’s likely time for a new water heater anyhow.
Thanks for the quick replies. I thought keeping the energy on for a while then turning higher to make things more comfortable was more efficient. Consider ignorance fought!
You can get a digital thermostat at Lowe’s for approx $50 that let’s you program in up to 4 different temperature times during the day/night. For instance during the summer, Night can be 72, Day 84, Evening 78, etc.
ETA: You get to set the times, so you can set it to start cooling before you come home from work. Also, it’s easy to install yourself.
You can get a pool timer and set it to turn the heater on for an hour before you get up, and then off again. Same for the evening’s dishes.
There is one issue with this, and it’s hard to get around: If you do this, and then one nice, cold day in the winter you get up at 4:30 AM to catch an early flight, you are going to have to take a cold shower, unless you remember to turn the timer off the night before!