The Cold Water Sandwich Effect and How to Stop It
We’ve all been there; you quickly jump in the shower to get the day started, maybe to warm up right out of bed or rinse off after an early-morning workout. You’re enjoying the hot, relaxing water when all of a sudden it turns cold as ice. You yelp and hop backwards to avoid the chilly stream, only to feel the water warming right back up again.
This is what’s known as the cold water sandwich effect, a rude and unwelcome surprise no homeowner wants to experience. But what exactly is the cold water sandwich effect, and why or how does it happen? And most importantly, is there anything we can do to stop it?
Continue reading to answer all of these questions and more, and to learn about potential solutions to this dreaded cold water surprise.
How does the cold water sandwich effect happen?
In appliances that experience the cold water sandwich effect, there is generally some warm water in the piping or stored at the mouth of the faucet, showerhead or any water outlet that is being used. So, right when you go to turn on your shower or bathtub, you will initially feel the stored-up heated water rush over you.
After this warm water is briefly released and the rest of the water in the storage tank is being heated, a small amount of cold water can get through the heat exchanger. This is where the icy surprise comes from.
Where does it happen?
If you haven’t already experienced the cold water sandwich effect in your own home (and trust us, you wouldn’t forget it if you had), it’s important to note that the cold water sandwich effect most commonly occurs in spaces that use tankless water heaters or any type of electric water heater.
Tankless water heaters heat water as-needed, which saves money and energy in the long run. But, this also means that you have to wait (usually a very short period of time) for the heating elements and water itself to heat up.
As for electric water heaters, they generally take a few minutes to reach their optimal temperature levels. Gas powered water heaters, on the other hand, reach operating temperatures almost as soon as they’re turned on.
Ways to Eliminate the Cold Water Sandwich Effect
There are a few ways to eliminate the cold water sandwich effect, each with pros and cons of their own.
- Install a recirculating system, a plumbing addition that will quickly move your hot water supply to appliances and return cold water back to the heater with the help of flow check valves. These systems may solve the cold water sandwich effect, but they can also overwork your water heater, leading to greater energy usage and a shorter life for your entire system.
- Another option is installing a small, separate tank water heater and connecting it to your existing tankless water heater via the recirculation system. This protects your tankless water heater from being overworked and it keeps energy costs down.
- Look into installing a tankless water heater that is specifically designed to not shut off when water taps are closed. You can also choose a system that keeps the water supply circulating for a designated period of time after the water is shut off, just in case you decide to immediately turn it back on again.
- If you’re washing the dishes or taking a bath, leave the hot water tap running. This will keep hot water circulating and ensure that the heating mechanism isn’t having to switch on and off, therefore avoiding any hot water disruptions.
- Keep water heater filters and systems clean! Water heaters fill up with debris and sediment over time. This can affect water pressure as well as cause temporary hot water disruptions. To keep your hot water systems running optimally, make sure you’re conducting or scheduling the appropriate, recommended maintenance for your systems.
Contact a Professional Plumber
If you have questions about any of the products you can install to solve your cold water sandwich problem, or if you’re not sure where to start, contact a professional plumber. At Lenox Plumbing, we can answer any of your questions about the cold water sandwich effect, as well as help you determine the best solution for your home and your water heating system.
We also recommend scheduling regular maintenance for your water heater to get ahead of potential water temperature issues before they start. Give us a call or fill out a form on our website to get started.
