If your house is like ours, you use a lot of hot water over the holidays. Most of the water household will use throughout the winter months involves heating that water for washing ourselves, our clothes, our dishes, and, in many cases, for hot water heating via radiators. Here are some tips on how to get more hot water for almost free.
Water arriving at your house from the municipal system is usually between 52 and 55 degrees Fahrenheit. So in most cases we heat that water by 60 to 70 degrees or more. Your hot water heater heats water and pushes it into the outbound pipes on demand. It is not uncommon to have 30- to 60 feet of hot water pipe running through a basement or crawl-space. Most of the time, these pipe runs have zero insulation to keep the water from cooling down.
Without any insulation on these pipes, depending on their length, the heated water can cool by losing 10% to 15% of its heat by the time it reaches its destination. That means 10 to 15% of your natural gas or oil or electricity used to heat water has been wasted.
After wrapping the hot water pipes in the basement, we boosted the temperature of the water coming out of our faucets between 10 and 15 degrees Fahrenheit (F).
To do this, all we needed to know is how many linear feet of water pipe you have and what the diameter of the pipe is (usually 0.75 inches, but check to be sure).
Most home supply or hardware stores sell a polypropelene (foam) pipe insulation in 3 foot lengths that has a peel-off, self-adhering closure to hold the the wrap securely in place. The only tools required were a tape measure and a pair of scissors to cut the wrap to the right lengths for elbows and brackets. Even better, this pipe wrap is not expensive.
Just for fun, we put a thermometer on water heater's outbound hot water pipe. This showed a reading of about 100 degrees F on the dial. As you can see from these photos, the surface of wrapped pipe has a temperature of 83.5 degrees F, while the surface of unwrapped portion is 108 degrees F.
Before I wrapped the pipes, the hot water at the kitchen faucet rarely went above 105 degrees Fahrenheit. Now, it climbs to 120 degrees F–plenty hot for scrubbing those holiday pots and pans.
Our showers are hotter. Our dishwasher's "electric heat boost" no longer turns on. And the whites in our laundry get an even hotter dose of hot water. In short, the water was even hotter than we really needed it to be.
Bottom line: We were able to lower the thermostat on our hot water heater by a few degrees. Reducing the thermostat setting for the water heater tank will permanently lower our natural gas bill, all year round, while still giving us water that is hotter than before we wrapped all the pipes.
PS: Big shout out and thanks to John for letting me borrow the infrared camera!
Note on the numbers: Our natural gas bill is $39 per month (cooking, domestic hot water and one small hot water radiator loop for a sunroom). It cost us less than two months of natural gas bills to insulate all the hot water pipes (and I used all the left over wrap on some of the cold water pipes). If we save 10% on gas by having our thermostat lower and running less hot water before we get the temperature we want, this small project will pay for itself in less than a year. But getting more hotter water faster was worth it, regardless of this excellent return on investment.