Energy Failures in Central Domestic Water Heating

In an earlier post, I gave statistics from a California state funded research project on central water heating systems. The goal of the project was to determine how energy flows through the system. From the initial raw energy of natural gas that is input to the system to the end-use of the energy, which is the hot water that we use for our showers, sinks, and washers.

Here is a graph from HMG, the engineering firm tasked with the research, from their 2010 Hot Water Forum Presentation (Click here for source).

Their research shows that only 29% of the energy input is actually used for its intended purpose.

Doesn't this seem like a massive failure for energy efficiency and central domestic water heating systems?

We are losing 70% of the energy, which is astounding to me. The two biggest factors, water heater losses, which is energy lost from combustion, standby tank heat losses, and transfer of heated water to storage tanks, and distribution losses, which is heat radiating from the hot water piping that is run throughout the interior (and in worse cases exterior) of the building and exacerbated by running a recirc pump continuously which is keeping the piping out all the time, whether needed or unneeded.

These numbers represent a call for the technological advancement of water heating. Here are some ways to reduce these inefficiencies.

1. Upgrade water heaters - Water heaters and boilers have advanced in their efficiency, but since they last so long, most buildings are using water heaters which an efficiency rating below 0.62. Boilers and tankless heaters also have higher ratings.

2. If you water heater does not have a flue damper, add one.

3. Insulate all piping. If it's accessible, great. If not, make this a requirement for any future re-piping jobs. Even if it is within interior wall space, they should be insulated.

4. Control the circulation of hot water. There are three basic options, timers, temperature sensors (aquastats), and demand pumps. You already know I'm going to suggest demand pumps, but the third party research published the 55% reduction in heat losses from our systems, not us.

Secondly, I am in dozens of boiler rooms every week, in almost every case I run into timers and aquastats they are overridden and not doing anything. During holidays, or during a power outage the timing gets screwed up and next thing you know the maintenance manager has deactivated these devices.

So if you are ready to make some easy changes, that will save energy and money. Give us a call and visit our website. Enovative Kontrol Systems.