Insulating Motorhome Water Tanks

Insulating a motorhome’s water tank is an issue that may come up when a new motorhome is purchased or when a new water tank is installed. Insulating a motorhome tank can take some of the risk out of storing it in freezing temperatures, but is it worth the expense and trouble?

Most new motorhome water tanks come already insulated, so you shouldn’t have to worry about insulating them other than protecting hoses and connections. Older motorhome water tanks may not come with integrated insulation and would benefit from being insulated from the outside.

Motorhome water tank insulation can help protect damage to the water tank in cold weather. Keep reading to learn more about insulating motorhome water tanks.

Why You Should Insulate a Motorhome Water Tank

There are several reasons why insulating a motorhome water tank can be beneficial, especially if you’re purchasing a used or older motorhome. Here are just a few of them:

Insulating the water tank prevents freezing. A frozen freshwater tank will prevent you from being able to use water in the motorhome, and can also cause damage to the connections and fittings in the system. This is an important consideration for those who store their motorhomes regularly in below-freezing temperatures.
Insulating the water tank protects older water tanks. Many newer freshwater reservoirs in motorhomes come pre-insulated to prevent freezing up in cold weather. however, older motorhomes can benefit from not only getting the water tank insulated, but also insulating the rest of the plumbing in the motorhome as well.

How to Insulate a Motorhome Water Tank

When it comes to insulating a water tank in a motorhome, there are a few different ways you can get the job done. These are some of the methods motorhome owners can use to winterize and insulate their water tanks:

Spray-on insulation: Spray-on insulation is an effective way to add insulation to a motorhome water tank. However, this method can be somewhat messy if there aren’t steps taken to contain the overspray to the water tank. Keep in mind that the water tank may need to be removed from the motorhome entirely to insulate it with this method. (Source: Motorhome Fun)
Water tank heat panels: Water tank insulation panels are designed to be attached to each side of the water tank to provide a layer of insulation against the cold. (Source: Jayco Owners Forum) Water tank heat panels are a tidier option than spray-on insulation, but it may be difficult to find the right size for some motorhome tanks.
Water tank heater blanket: Like the heater blankets constructed for in-home water heaters, a heater blanket can be wrapped around the freshwater tank and electrified in the same way that heater pads operate to keep the water in the tank above freezing temperatures. (Source: Unique Camping Marine)

Each of these systems can help keep the water tank itself from getting so cold that the tank freezes with water in it. If your motorhome water tank freezes, you can end up with some serious problems.

What Happens if the Water Tank Freezes?

Why would people go so far out of their way to keep the water tank from freezing? If the problem was just a delay in water services in the motorhome until the system thawed out, many people would just put up with the issue.

However, when water gets turned to ice, this causes it to expand. In a motorhome water tank that is full or almost full, the expansion of the ice puts pressure on the tank walls, and this can cause them to crack. If the water tank cracks, all the water can potentially drain out of it and leave the motorhome with no freshwater access.

For someone in the middle of a cross-country trip in their motorhome, suddenly finding themselves without cooking and bathing water can be a major inconvenience. Add in the cost and hassle of trying to get a motorhome water tank fixed on the road, and you’ll see why many people prefer to make sure their tank is protected ahead of time.

How Much Does It Cost to Insulate a Tank?

The cost of insulating a motorhome water tank depends on the method you choose. 12-volt heater water tank pads can cost between fifty and a hundred dollars apiece.

However, since each pad can be applied to fifty gallons of water and usually come in packs of at least two, one heater pad placed on the most easily accessible side of the water tank can usually keep the entire thing from freezing.

The major disadvantage of using a heater pad for your water tank is that it has to have a constant electrical setup to work. If the electricity fails on the motorhome during freezing weather, the water tank will be susceptible to freezing.

A much more costly option than using a heater pad is to use spray-foam insulation. These kits can cost almost eight hundred dollars, but provide a more permanent and stationary solution to the water tank insulation problem than heater pads. Another disadvantage of spray-foam insulation kits other than their high cost is their messy application. This can cost extra time.

Do You Need to Insulate a New Water Tank?

While adding insulation to a motorhome water tank does have its advantages, there are a few instances where you might want to hold off on doing it. Here are a few scenarios where you should consider not insulating your motorhome water tank:

You are planning on replacing the water tank. Many new freshwater tanks for motorhomes come pre-insulated to prevent freezing. Check with any new water tank model to see if it already comes with insulation built into the construction material. If so, additional insulation is usually not necessary.
You don’t live in a cold weather climate. The other instance where it may not be worth your trouble to insulate a motorhome is if you live in a tropical climate where the motorhome will not freeze. Even in many temperate parts of the world, temperatures may not regularly drop low enough to make insulation an issue.
The water tank is already damaged. If you have a motorhome water tank that already looks like it is developing cracks, adding spray-foam insulation can expose the finished insulating foam to your water supply. This can be dangerous if the spray-foam isn’t chemically stable and puts off contaminants in the water.
The motorhome is stored in a temperature-controlled environment. For people who are lucky enough to be able to store their motorhome in a large garage and don’t intend to travel to cold weather areas much, the temperature control of indoor storage can protect water tanks from freezing without additional insulation.

The more you plan to take your motorhome into frigid temperatures for travel, the more important it is to prepare your water supply. Conditions that may not threaten your water tank at home may put in you a motorhome service station after the fact if you end up in freezing weather on the road and bust your water tank.

Are There Downsides to Insulating a Water Tank?

There aren’t many drawbacks to insulating a water tank, even if you don’t expect to encounter below-freezing temperatures very often. However, there are a few downsides to insulation that should be taken into consideration:

Insulation and freezing: While insulating a motorhome water tank can help keep it from freezing, if you insulate a tank and it freezes anyway, it will take that water tank much longer to thaw out due to the insulation. Keep in mind that insulation doesn’t just work for retaining heat. It prevents the loss of cold, too. (Source: Out and About Live)
Added expense: No matter which insulation method you choose to insulate your motorhome water tank, adding insulation will cost you an investment in funds either way. For some motorhome owners on a budget, this added cost may not be worth the relatively low risk of their system freezing up.
Added work: For motorhome owners who opt to insulate their water tank with spray-foam insulation, the insulation job is both expensive and tedious. In many cases, spray-foam involves pulling the water tank out so that all sides can be covered with the spray-foam evenly and no additional foam is spilled or splashed elsewhere.

Depending on where you live in the world, insulating motorhome water tanks may not be worth it. But it may be a good idea to keep some water tank heater pads on hand just in case you get caught in sub-freezing temperatures.

Insulating Removes Risk

Most people don’t consider the insulation on their homes or motorhomes until lack of insulation and burst pipes or water reservoirs makes the situation an emergency. But going out of your way to insulate your motorhome water tank ahead of time can prevent you from having to worry about a busted-tank catastrophe down the road.