Drain your water heater, increase efficiency

Water heating is commonly listed as the second highest energy load in the home.  Of course this depends on how big your family is, and what energy source you use to heat your water (electricity or natural gas).  We use natural gas, and based on how low my summer natural gas bills are (we also use natural gas for winter heating) I know that heating our water isn't costing us that much (maybe $7/month).  With that said, there are a few things you can do to decrease your water heating bills, and draining your water heater is one of them. Yesterday I drained my water heater for the first time in over 3 years.  The purpose of doing this is to clear out any sediment that may have settled on the bottom of the tank.  The amount of sediment that may collect in your hot water heater storage tank depends on the quality of the incoming water, but you really don't know how clean or dirty it will be until you do it once or twice. I followed the steps from DIY Network on How to Drain a Water Heater.  Make sure to read that post and also read your water heater's instruction manual.  The important things to remember are cutting off your power source (electrical breaker or natural gas) and shutting off the cold water intake.  You also want to open up a hot water faucet inside to prevent any water or air from getting stuck in the lines.  But I don't want to oversimplify the process, so read the above link!

My results were pretty underwhelming.  There was some sediment, but I'm not sure it if justified wasting a whole bunch of hot water in my driveway. The process did help me learn that my water quality is pretty good, so I probably don't need to do this every year. Energy Savers also recommends the following, which may make more sense for me going forward:

Drain a quart of water from your water tank every 3 months to remove sediment that impedes heat transfer and lowers the efficiency of your heater. The type of water tank you have determines the steps to take, so follow the manufacturer's advice.

I'm curious to hear if some of you have done this and what your results were.  One thing I did notice was that the hot water supply pipe from the water heater to my home has about 2 feet of exposed copper piping!  I've lived in the home over 3 years and never really paid attention to this.  Heat is escaping from this pipe into my garage area, so I'm going to head to the hardware store and pick up some pipe insulation asap! Aside from draining your water heater, here are some other things you should read if you are curious about saving energy related to heating water:

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My water tank leaked after 3 years and I got and installed a replacement. Within a year I added a recirculating pump to get me almost instant hot water for my shower 2 stories above my water heater tank. With this set up I believe the sediments can't settle because of the scheduled constant motion of the water. So far it has been 8 years since I changed the 4 year guaranteed tank and I've never drained the tank. My original leak occurred on the top of the heater, The dielectric connectors used were the $0.50 ones. When I did my own tank replacement I splurged for the $5.00 ones lined with plastic. I think that has also helped. I'm ogling the hybrid tanks with heat pumps and also the marathon water heaters with lifetime warranty in the event of needing a replacement.
I've drained mine exactly once in the 10 years we've lived here, I'm ashamed to say! It's now 10 years old; probably time to look for a new one before it leaks. I really hate to put in another bog-standard tank heater (even if the EF will jump from .53 to .69 or so). I'd considered tankless, but our ground water is so cold in the winter, I'd have to buy a really big unit to get the proper temp rise. And there's no room on the roof for solar hot water; that's all filled with PV! So if we go with another tank I will at least drain it yearly in the hopes that it'll last a bit longer. A couple years ago I did insulate as much of the hot water piping as I could reach. It made a noticeable difference at the tap, and I was able to turn the heater down a bit and still have 120F water at the tap. That's a -really- simple upgrade.
ckmapawatt's picture
That's my next post Eric! I spent $2.49 at home Depot today to buy some insulation for the copper piping. Do you use natural gas or electricity to heat your water?
I forgot to mention that my electric hot water heater is at least 26 years old (it was here when I bought the house) and I have never drained it. Not once. It still works great. David
Natural gas here.
I can see how flushing the sediment out of a gas, oil or propane hot water heater could improve its efficiency, but how could it make a difference with an electric water heater? The combustion based water heater heats the water from the bottom and the sediment could insulate the water from the flame. But in an electric hot water heater, the heating is done by two elements, one toward the bottom of the tank and one near the top. The sediment would have to be many inches deep to cover the bottom element -- possible but not likely. Replacing the element (a simple procedure) would make a lot more sense. David
Wow! It never occurred to me to incorporate draining our hot water heater into our home maintenance plan! Although, I am noticing some nay sayers on this topic, I will do some research as well!
I also forgot to mention why replacing the heating elements on an electric hot water heater makes sense: they get covered with scale, at least some do. The scale acts as an insulator. I doubt replacing the element would make any difference in your electric bill, but it might make the tank heat up faster. David
I insulated the pipes and added a insulating jacket on the hot water heater. Can't say I have ever drained it.
I agree with David Fay. I've been a contractor with a good deal of experience with water heaters. I'm not sure that sediment will really affect a heat transfer issue that could be correlated with any noticable savings. Insulating the pipes is, of course, a very good idea.


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