After installing insulating foam.

Two Cheap and Easy Water Heater Money Saving Tips 1


As we wrap up our Holiday vacation here at the Utah house, I’ve been tinkering with some home improvement projects (part of how I relax on vacation really is by fixing stuff). So today, I did two quick, cheap, and simple projects today to reduce the energy use of our water heaters.

Tip #1: Turn Off One Water Heater

We have two water heaters in the Utah house’s utility room, which are connected “in series,” like this:

Two water heaters connected "in series."

Two water heaters connected “in series.”

This is a common setup in modern houses, since buying two 50 gallon water heaters is generally cheaper than a single 100 gallon unit. And, assuming you’ve got them plumbed with the appropriate shut-off and bypass valves, it gives you dual-redundant system, so that you can operate on a single water heater if one dies, and you can swap in a new one without depriving the house of hot water.

In most series water heater setups, Tank #1 does the majority of the work (and uses the most energy) to heat up cold water. Tank #2 then stores the water heated by Tank #1, and burns gas occasionally if the water isn’t used before its temperature drops.

What I did today, however, was turn the thermostat on Tank #1 down to its lowest setting. Because the incoming cold water here in Utah is really cold (especially in winter), Tank #1 will take over the job as a storage tank, using ambient temperature in the basement utility room to bring incoming cold water up to room temperature. Tank #2 will then burn gas like Tank #1 used to, but it will be actually using less energy because the starting temperature of the cold water will be 20-30 degrees Fahrenheit higher than normal.

The downside to this approach is that there will be less overall hot water in high-demand situations, but that really doesn’t happen that often at this house. In situations where we have lots of people wanting to take showers, then I can fire up Tank #1 again and have lots of hot water available. But I estimate I can save at least $40 a month off my gas bill with this one trick, and I most likely won’t notice anything different at shower time.

Even if you only have one water heater in your house, you can still lower its thermostat, since every degree cooler you go is money in your pocket. Maybe try nudging it down just a tick or two, and see if you (or anybody else) notices. If not, then you’ve been overheating your water, and wasting money.

UPDATE: After running like this for less than a day, I noticed I could hear the burner on Tank #2 firing more often than normal (meaning more often than it used to run on Tank #1 when it was the primary heater), so I thought it about the setup some more… and determined that this approach will work fine for homeowners with two water heaters in series… unless you have a recirculating pump that returns warm water to Tank #1 (like I currently do). With the recirculating pump running, it’s pulling warm water from Tank #2 around the house, then pushing it into the bottom of Tank #1. The hot water then cools somewhat when it hits the cold water sitting in Tank #1, but the pump also forces cold water from Tank #1 over into Tank #2, even when no hot water faucets in the house are demanding hot water (the pump is essentially creating the demand). When enough cold water hits Tank #2, the burner fires up to bring it up to temperature. And that’s happening way too often.

So for now, I’ve switched back to my original settings, until I can re-plumb the recirculating pump to push water into Tank #2. Look for a new blog post soon! 🙂

Tip #2: Insulate Your Exposed Hot Water Pipes

As I worked on my humidifier and pressure gauge plumbing project this week, I decided I wanted to insulate any of the hot water pipes I could see in the utility room. If I can see them, that means they’re exposed to the air, and are radiating (and therefore losing) some amount of heat into the air.

Exactly how much energy I’m losing this way is hard to tell, but insulating them is extremely inexpensive, so even without knowing exactly — it’s still the right thing to do. Out of curiosity, I took a few readings with my brand new Fluke 62 MAX+ IR Thermometer that Santa brought me this Christmas just so I’d know how hot the exposed copper pipes were on their exterior surface.

At the local hardware store, I picked up five 6′ insulating foam pipe covers, each of which cost $1.18 each. For less than $6, I was able to cover all the hot 3/4″ copper pipes I could see in the utility room (including the copper flex hose that connects Tank #1 to Tank #2). Here’s the “before” picture (which is actually the “after” picture from the above-mentioned humidifier and pressure gauge project):

Before installing insulating foam.

Before installing insulating foam.

And here’s the after:

After installing insulating foam.

After installing insulating foam.

Again, all the material cost less than $6, and I had about 3 feet left over. Next time I’m down here, I plan to use some black duct tape to secure the ends of the foam around the fittings, just to have a more snug fit.

After finishing this project, I waited a few hours to allow the foam to heat up and then took another set of readings with my IR thermometer. The foam was between 15F – 20F cooler than the exposed pipe, which confirms they’re doing their job.

Insulating is an often overlooked method of saving a lot of money over time, by spending  a little money and time. I’ve got some blog posts planned in the future as I try to tackle some weatherstripping and insulation projects this winter (stay tuned!)

That’s All, Folks!

These two water heater tips are quick and cheap, and guaranteed to save you money. If you have any quick energy saving tips of your own, please feel free to leave them in the comments. You just may give me an idea for my next blog post! 🙂

  • Alo Pexoma

    What about simply running water heater #1 at a lower temperature(something like halfway between off and whatever tank #2 is set to)? It becomes a lower temp holding tank for #2. It still burns quite a bit less energy, and so suffers less overall heat loss. The recirculating pump is ultimately pushing lukewarm water into tank #1 anyway, so there’s less worry that it will be cycling needlessly due to extra cold water throughput. Tank #2 still does the bulk of the heating work, but still does considerably less overall work than #1 would do by itself.