This is a perception that is most commonly noted by owners that have recently switched to a combi-boiler or a tankless water heater after moving away from using a heated storage tank to produce and store Domestic Hot Water (DHW).
Heated Storage Tanks - The water contained in such a water heater is being heated throughout the day and night, regardless of whether you are using it or not.
The benefit of course, is that the stored water is already hot and ready for use at any time.
However, that means that energy is being used just to keep a large supply of hot water on standby. You are paying to heat and store water all the time, just to use it sporadically through the day.
In addition to the ongoing energy use, you will also only be able to use as much hot water as the tank can store, and once the hot water is depleted, you will need to wait until the fresh cold water has been heated up and ready to use.
Combi-Boilers & Tankless Water Heaters - These types of water heating products only produce hot water when the owner opens a hot fixture somewhere in the home.
This means that no hot water is stored in the product, and so when you open a fixture in the home the water heater will ignite and then start heating the cold water that is flowing through its heat exchanger now. That does mean that there is a small delay in the delivery of hot water to the fixture, and if you previously used a heated storage tank you may notice it.
The benefits though, are significant:
- You are only paying for energy while the product is activated and producing hot water on-demand. When you close the hot water fixture, the product is going to shut down and go back into standby mode.
- You are not limited to a fixed amount of hot water that will deplete and then run cold. As long as you have a hot water fixture open and the product has activated, you will have endless hot water from that fixture until you close it.
Regardless of whether you are using a heated storage tank, a combi-boiler, or a tankless water heater to produce your home's hot water, there is another delay that must be recognized.
There will still be a delay in the delivery of hot water as the plumbing between the product and the fixtures will contain cold water that will need to be pushed ahead of the hot water that's heading towards the open fixture.
Simply put: The longer the run of plumbing, the longer it will take for the hot water to arrive where it's needed.
For the majority of users, the small delay in hot water being produced and then reaching their hot fixtures is of no concern. It is a normal dynamic of hot water that is produced by a combi-boiler or a tankless water heater, and the owner is instead focused on enjoying the lower energy costs!
- If you have a fixture that is particularly far away from the water heating product, and it's one that you frequently use and the delay is problematic for you, then you could use an electric mini-tank water heater as booster. These water heaters are typically 120v and should be installed close to the distant hot fixture and in-line between the main water heating product and the distant fixture. For further details regarding our family of Tronic 3000T electric mini-tank water heaters, please visit this page.
- If you would prefer to reduce the wait time for hot water at all hot fixtures in the home, then we recommend consulting a licensed plumber to discuss the options for installing a recirculating hot water plumbing arrangement. Please visit this page to search for a contractor in your area. Typically one loop of hot water plumbing will leave the water heating product, travel around the home, and then back to the product. Short plumbing lines to each hot water fixture will then branch off the main loop. A pump and a timer will be used to circulate the water around that loop occasionally, which will also activate the combi-boiler or tankless water heater, and leave hot water in the plumbing loop around the home. The next time you open a hot water fixture, you will have less of a wait time for cold water to flush through, as it is pre-heated from the last time that the recirculation pump ran.
Important! Before deciding to install a recirculation loop, be certain that your combi-boiler or tankless water heater can safely be installed in such an application. Some models are designed to be supplied with cold water only and may be damaged if supplied with heated water that is returning from a circulation loop. Consult the literature that came supplied with your product. If you no longer have the printed literature that came supplied with your product, an electronic copy can be downloaded from our manuals download page.