Nathaneal, did you think about having the heater in your shed/garage or wherever and heat the water as it went into your tank?
You'd have to start the process early in the morning would be one drawback I think.
Or is your water heated from cold when it comes out of the tank and into the di resins?
If you ahd the heater in the garage this would save space in the van.
Sorry,.. missed this post yesterday!!
It is possible to heat the water at home,.. I know a few DI only guys have tried hot by filling up from the kitchen hot tap in the morning!
The reasons I don't do it this way are:
1. It'd use a lot more gas, eg. Heating an entire tank when some days I come home still half full.
2. I'd be stuck with hot,... with single glazing or historic glass I turn the heater off.
3. Hot water will reduce the lifespan of the pump.
The water doesn't really need to be very hot at all to make a difference. In the winter you really notice the difference. I've a digital thermometer in my van tank, and last winter I was cleaning windows with water below 3 degrees Celcius. Being a bit paranoid about cracking glass from the heat, I had the heater set to its absolute minimum when I first installed it, which heated the water to 22 degrees,... it really made a big difference even at that lukewarm temp!
Most days I work at about 40 Degree's,.. not very hot, but it really makes a difference.