I had asked in heating and cooling and didn't get any responses, so I thought I'd try here since it sort of applies. I have always read that when you have gas or the like furnace, over-sizing can kill your efficiency because of the short cycles. This makes the furnace not get up to peak efficiency. With electric, does this still apply? Because electric heat is 100% efficient, in my mind, an over-sized baseboard for a given room won't effect the cost of heating. I imagine that the elements might take a few seconds to get up to peak heat, but after that it would just cycle on and off as heat is required, correct? The reason I ask is, everywhere I've read says that for baseboard heat, multiply the room dimensions by 10. So I did a heat loss calculation on my living room for example. It is aprox. 230 square feet. So a baseboard that is 2300 watts would be correct using the 10 times model. But I did a heat loss calculation for that room. Took into consideration the temp difference from outside in winter, the size and type of windows, the R value of insulation in the walls and ceiling, and whether there was a heated space below. And because it's a new house (brand new with tight design) it calls for a baseboard of about 1500 watts. But I wouldn't want to undersize the heat, that's for sure. Maybe 1500 watts is okay, but its not a stretch cost wise to go to say 2000 watt, or 2500 watt even (other than the larger physical size). But if I did go that large, just to be safe, would that be a bad idea, by making it less efficient? I hope I'm making sense... thanks.

Electricians only know how to wire electric heat, we do not know how to do heat loss, well, at least speaking for this electrician.

Efficiency is a combination of things. The smallest heater that will do the job will be the most efficient. Think of it as a trip to the store in your vehicle. You can simply do the speed limit, make your stops and get there... or you can floor it then slam on the brakes at each stop until you get there. Which seem more efficient to you? A larger heater will heat the space faster... period. But the trade off is in electrical energy. Simple calculations can tell you which would be more efficient. If you need instant heat, chose the larger heater and turn it off when you don't need it.

I'm no electrician. A regular light bulb turned on and off many times a day to save minutes/hours of electricity is more efficient than leaving it on because no energy is wasted turning it on and off. I would imagine that electric baseboard heat would take some amount of time to get warm, and thus a certain amount of loss of efficiency by cycling on and off. So the answer will depend on the product and how long it takes to produce heat. The manufacturer would know.

I tend to agree with joypulv, as since there is no "extra" energy needed to turn off and one, unlike a gas furnace, it would really come down to how fast it heats up. And I know baseboards don't take very long. So the question is, is the extra it takes to heat up, really going to be that big of a deal. Probably not. Besides, look at it this way, the heat requirements are based on heat loss during the coldest winter months. So during the fall and spring, when it isn't that cold outside, the heat is essentially way too large for those seasons. So really, I think this is a moot point now. I think as long as you have enough heat for the coldest days, then you should be fine all around, rather than risk not having big enough heaters etc. And the money saved by going with smaller heaters is so minuscule, I think I'll go with the rule of thumb on this one. Thanks again guys!