How Many Lightbulbs Does it Take to Heat a Tiny House?

Last fall I designed my tiny dream house in a workshop called Less is More, which was taught by Andreas Stavropoulos and Dave Cain at Yestermorrow Design-Build School. As I was deliberating about heating options, my classmate John joked, "Sheesh! That place is so small you don't need to install a heater - you, your cat, and an incandescent light bulb would heat the place right up!" John had lived on and built boats in Maine for decades so I took most of what he said very seriously. But I also knew I'm a wimp compared to him, so for the last year and a half I've been paying attention to different heating options for small spaces. Heating seems to be a dilemma for many tiny house dwellers. Some folks love wood heat so they install tiny wood stoves and stoke their fires and call it good. A friend of mine who is an arborist says wood is the way he'd heat a tiny house since he has a limitless supply of it. But crawling out of a warm bed to build a fire doesn't even sound fun to me when I'm camping! Besides, I'm a little pyrophobic. Even if I did like building fires I'd need to get good at it so that I could control temperatures so it was comfortable. And since my schedule often involves being gone for 12 hours at a stretch it I wouldn't be around to stoke a fire.

Taking a page out of Jay Shafer's book, lots of folks have installed propane boat heaters in their tiny houses. They have great ambiance (a flickering blue flame) and they heat a space up quickly and without the mess of wood. But in order get the heat distributed throughout the room you have to have the fan on. And the fan is noisy. Obnoxiously noisy. I have a hunch that when you live in central California heat's not quite as critical as it is during the winters here. Portland has a nice, mild climate, but we still have plenty of heating degree days! Brittany installed one of these propane boat heaters (which requires clearances, running a propane line, and adding an additional penetration in the ceiling).
By the time Brittany turned her little house over to me she had pretty much quit using her boat heater. Instead she had switched to a portable oil radiant heater which has a timer so that it can be set to come during certain periods. Unfortunately, it doesn't have a setback temperature so it would come on and bring the temperature up to the set temp from whatever the house had cooled down to. Depending on how cold it is this can take a while! At the end of the set time it again turns off completely. I found that it worked pretty well to just set the temp to about 60 degrees and manually adjust it whenever I wanted it warmer for a while. But it also took up precious floor space, I sometimes tripped over its cord, and it was a little clunky to have to move it every time I shifted the desk over to use it as a table for dining. So I started looking into other options.

space heater installed

Last week my new heater arrived and, as promised by the website, installation took just a few minutes. The new heater is a wall mounted convection heater with a nice slim profile and some sort of special stack effect technology. (I understand the stack effect - I think! - but I don't see how it can be very effective in a heater that is only two feet tall, so I put it on the near the loft so that the height differential can give it a boost.) The heater is made by a company called Envi and after reading reviews for the three heaters on the market that are similar, I went with this one because there's a temperature control and the design has curved edges which I figured would help me be less likely to snag myself on it. The others also had some reviews that talked about worrisome defects and poor customer service, but it doesn't help that all three of them have very similar names. So I sprung for the one that cost $30 more.

Which brings me to the notion that $130 is a lot of money to spend on a space heater - unless it's your entire heat system and then it's nothing! I like the slim profile and it seems to be heating up nicely so I'm impressed so far! It doesn't actually have a thermostat, but it does have a temperature control. I can turn it up and down as well as on and off. I can't tell what the temperature is in my tiny house. But there's only been one day since I installed it that I felt chilly (and that was after I turned it down because I'd gotten too hot). It was also right around the winter solstice. Short, dark, cold days. So for now I'm just keeping it at full tilt and appreciating that it's always warm inside my house.
Perhaps the coolest thing is that, unlike the oil heater which was a 1500 watt heater, the new one only uses 475 watts (basically like having five incandescent lightbulbs on!) Which, I'll admit, got me thinking of John's comment: it might actually be more cost effective in the short term to just swap out all the nice CFLs Brittany put in for incandescents since they produce so much heat I might not need a heater at all! But really I don't think they'd quite do the trick...