How To Keep Mice Out of Your Pool Heater

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Mice and other members of the Rodentia family are always searching for the warmest and safest places to make their nests and raise their families. Unfortunately, this can cause all sorts of problems for us humans.

Places mice like to squeeze into to make their nests include wall cavities, water heaters, stand-up air conditioning units, and your pool heater. To mice, your pool heater is an outdoor shelter with built-in heating, the perfect survival solution.

Why are mice an issue? Mice can cause significant damage to the electrical and mechanical workings of machinery like your pool heater. They also carry Salmonella and hantavirus. Here is a helpful guide on how to keep mice out of your pool heater. 

Check for the Presence of Rodents

The first thing you can do is simply make sure that no mice live in your pool heater. You can open it up about once a week, especially in wintertime when you’re most likely to need it, to see if you can identify any signs that rodents are inhabiting it.

If mice live in your pool heater, they will likely nest near the heating elements. You will see signs of nesting materials such as lint, fabric pieces, leaves, moss, and other soft and warm items they can easily tote back to their nests.

You will also potentially notice fraying of the wiring or bite marks in the rubber coating over the wiring inside the pool heater. This is because mice continuously chew and gnaw on anything they can.

You may only notice mice have taken up residence in your pool heater once it stops working one day. It is essential to check the interior regularly to prevent damage before it begins (or at least before it becomes severe).

Useful Supplies

Besides checking your pool heater, how can you dissuade rodent life from living in there altogether? There are some helpful materials you can purchase from any hardware store, and many dollar stores even have these materials you can use to protect your pool heater.

Here’s what you need to make your pool heater virtually mouse-proof: 

  • Hardware Cloth
  • Nuts and Screws or Bolts
  • Wood panels 
  • Rubber Snakes
  • Steel Wool
  • Mothballs

An important note: you cannot and should not run your pool heater with all these materials on the inside and outside. Make sure that before you turn it on for its intended purpose, you remove the paneling and mothballs, especially before you cook them or cause unnecessary damage.

Mouse-Proofing Your Pool Heater

Here are some steps you can take to keep mice out of your pool heater:

Deter Them With Mothballs

The first step to ensuring mice do not find your pool heater an attractive spot to live is to place some mothballs right inside the control panel. We don’t like the smell of these anti-moth devices, but rodents loathe these even more. The smell of mothballs will deter rodents.

Scare Them Away With Rubber Snakes

One fun thing you can add is some realistic-looking toy snakes. It might seem like a childish or nonsensical idea, but a mouse wouldn’t want to take a chance with something that remotely looks like a predator, so these could be an added deterrent.

Use Steel Wool To Block Their Path

You can continue the rodent-proofing of your pool heater when you don’t intend to use it for a while by breaking up steel wool balls or pads and stuffing the steel wool into any and every crack or crevice you see on the outside of the pool heater. Mice can fit through openings about the width of a pencil, squeezing their bodies through and chewing through material if necessary. 

Ensuring that all potential entry points are blocked with steel wool will make it nearly impossible for mice to use those cracks or holes to get inside the pool heater. If they do end up chewing (and eating) the steel wool to get inside, it will eventually kill them.

Cover the Outside of Your Heater With Hardware Cloth

You can then bolt sheets of hardware cloth to the outside of your pool heater. If you’re unfamiliar, hardware cloth is like fine metallic mesh. (You can also use it to make your yard mole-proof, but that’s for another day.) 

Cut a rectangle of hardware cloth for each side of your pool heater’s exterior, making it smaller than the actual side. Then you can affix the hardware cloth to the heater by using nuts and bolts spaced regularly. Hardware cloth with quarter-inch spacings should be enough, but you can use finer hardware cloth if you can find it.

Place Wooden Paneling on Your Heater

You can then cover the heater’s exterior with wooden panels. You can purchase wood panels that are already the right size to cover up the hardware cloth and sides of your pool heater, or you can cut them yourself from larger plywood sheets or thin planks. This wood paneling is to make everything look attractive as well as to hold your steel wool and hardware cloth in place.

If mice wish to enter your pool heater, they must attempt to get through wooden panels, hardware cloth with extremely narrow openings, steel wool, and then the atrocious stench of mothballs. This is an unwelcoming habitat for any rodent, and mice will not want to deal with the gauntlet you’ve set up on your pool heater.

What if There Are Mice in My Pool Heater Already?

If mice get into your pool heater and chew wires before you ever have the chance to mouse-proof the heater, then you have a few options.

You can try to remedy this issue yourself. Depending on the severity of the infestation, this could be a viable option. 

Make sure to shut off the power supply to the pool heater, so you don’t electrocute yourself. Then wear gloves and a face mask, so you don’t breathe in any dusty mouse droppings or urine, and spray the nests and other mouse signs with bleach. Leave everything for a few minutes, and then you can clean it all out with paper towels and place it into double-bagged trash bags.


Learning how to keep mice out of your pool heater will save you significant time and money. Keeping an eye out for the telltale signs of their presence is crucial. You want to prevent, deter, or block them as soon as you suspect you may have a mouse issue. 

If you notice mouse damage to the wiring, you may need to call the professionals. If the mouse infestation is severe, you should likely call an exterminator to get rid of the mice, and then you can get an electrician to set your pool heater right. 

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