When we converted the bus in June of 2012, the United States happened to be experiencing record high temperatures. Looking at the forecast, we saw that triple digit highs lay in our future. While insulation would help us beat the heat, it would take longer to install than would an air conditioner or two.
The Air Conditioners
In our design stages, we had planned on having an air conditioner in the front, above the driver seat, and one in the back. We weren’t sure if the number of units nor if the power chosen for each would be enough. Here is where we warn you to improve on what we did.
During an East Coast Summer, it has not been sufficient to have a 12,000 BTU mini-split in the front and an 8,000 BTU window unit in the back because there is a hot spot in the middle of the bus that stays warm. We could have gone with a 10,000 BTU rear and 14,000 BTU front. Another option would have been to find a rear unit that threw the air farther. The downfall with this solution is that a more powerful fan means more noise. When we put our window unit’s fan on high, it is so loud that we can’t hear our TV very well. The forward mini-split however remains quiet in the front but it does not throw its cool air far out enough. We could have used one with a more powerful fan on that unit.
Air Conditioner Install
During our first month of bus conversion, we didn’t have time to research and buy a mini split adequate for our needs. We were desperate enough, however, to buy the less complicated window unit. Off to Fleet Farm we went and purchased an 8,000 BTU window unit for a whopping $89 at sale price, originally a couple hundred dollars.
Most window units project from a room’s fenestration to grab fresh air and to spit out the hot air made from making cool air. Just as we didn’t want to have anything popping out the roof, we didn’t like the idea of an air conditioner sticking out the back of our bus like a caught-and-forgotten toilet paper trailing down someone’s underwear. Faced with the criteria of keeping the air conditioner within the bus’s envelope and still needing to vent the unit, we placed it in the nook above the engine compartment.
With a load of fear and a dash of determination, Michael cut two holes at the bus’s sloping rear facade. These would accommodate the two vents we bought for a mere $14 each. Armed with a rivet fan spacer and a rivet gun, he covered the holes with vents initially intended to vent attic spaces. The next step was to create a box around the AC that also covered the air space leading to and from the vents.
With this sub-project complete we were now finally able to focus our efforts on insulating the bus walls and ceiling.
We decided to use a spray foam insulation because it was going to be easier to apply and more insulating than rigid or batt versions. Michael found a brand online and had it delivered to the farm early in our visit. We didn’t use it though until much, much later because of the tasks to be completed before installation. We had to finish all the welding, electrical and prepwork, like masking surfaces we didn’t want to spray and spot-foaming hard to reach places with a canister of cheaper foam insulation. This video illustrates the steps in applying Foam-It-Green insulation.
One tank ran out more quickly than the other, but that didn’t deter Michael for continuing to use the leftovers. Unfortunately, both chemicals are needed to make the insulation and we ended up with a blue liquid splattered here and there. In addition to that mess, the foam had blown up past where we needed it and a giant trim job lay before us.
I function like a work horse while Michael will spend extra time thinking of shortcuts. Before Michael had thought to use the Sawzall, I was using an exacto and slowly hacking away the excess insulation. It was actually quite meditative – a welcome change to the incessant labor! There was something satisfying about seeing a sharp blade cleanly slice off unwanted pieces. But I agree that it took too much time that we did not have to spare.
Exasperated with how much work we still had left to do, Michael grabbed his Sawzall and artfully & quickly trimmed the entire bus’s insulation in one hour.
Death Averted, Air Cool-Converted.
We luckily finished both the air conditioner and spray foam installation before Mother Nature blessed the Midwest with 3 days of temperatures above 100°F. Combining the roof’s heat-reflecting paint, the insulation and the conditioned air made a world of difference in providing us comfort. If we had to do it over again, the only change would have been to get a more powerful window AC.
What have you used or plan to use in your bus conversion? Technology has changed in the 4 years since we did ours – maybe you can provide insight on the better options.