In Part 6 we wrote about our decision to decline for now both offers from different firms to install the Rinnai natural gas tankless water heater for the reasons specified in that article.
What I would like to do now is to begin (and there truly is so much information available that one can only start to) to elevate the debate between which energy source, natural gas or electricity, is preferred for a tankless / instantaneous hot water heater. I am not a scientist, engineer, home builder, physicist, etc. I am simply an average home owner. But, I do not rely on someone posting a message or comment in an Internet forum saying that this or that is the only right way to go … and neither should you. Anyone can type such a message … yes, including myself. What I will do is seek out information from numerous sources who seem to be credible. So, many links are provided below for you to see the source of the information contained herein.
First, here is a link to a very short (1 minute) video from ToolBase Services (housing industry resource for information on building products, materials and new technologies) explaining tankless water heaters.
And, here is what the inside of a tankless water heating device can look like. This one is of an electric tankless water heater.
From a pure energy conservation perspective, a true solar hot water heating system to me is preferred as it emits zero direct and indirect carbon emissions into the air as it’s energy source is the sun.
Have you looked at the cost for one of these? According to the Americal Council for an Energy-Efficient Economy (ACE3), their estimate for a solar hot water system with an electric back-up is around $4,800 before any incentives. Yikes! I want to go green as much as the next person but not at the cost of needing to take out a bank loan. With the State of Hawaii now requiring solar water heating systems on all new homes starting in 2010, hopefully the prices will come down.
The next environmentally friendly tankless water heater to me would be an electric tankless water heater. Why? First it consumes no non-renewable resources (like natural gas, propane or oil).
Second, less electricity is being generated by consuming non-renewable sources such as wind farms, solar farms, etc. The same cannot be said for natural gas tankless water heaters.
Third, when in use (and when in stand-by mode) it emits no pollutants in the air. Compare this to a natural gas tankless water heater that will emit pollutants in the air.
Don’t believe me? Why do you think that you need to have special venting with a natural gas tankless water heater over and above what is needed for a natural gas hot water tank (please see Part 2 and Part 5 articles in this series for the placement of the natural gas hot water tank proposed to us by two different firms). This is way more venting than you need for a natural gas hot water tank!
With an electric tankless water heater you have no such special venting need. Firms such as SEISCO provide tankless electric water heaters that can be installed anywhere in the home: basement, attic, closet, stairwell, etc. with no venting of any kind! How do I know if I am just an average home owner?
I personally don’t. However, here is a link to a video from the PATH (a Public-Private Partnership for Advancing Housing Technology) concept home demonstration site describing the SEISCO electric water heater (in the upper right within the SUSTAINABILITY section of the new window place your cursor over “Tankless Water Heater” and then select the video camera icon to the immediate left).
What about the cost to the home owner of a natural gas vs electric tankless water heater? The quotes we received for two firms for the same the Rinnai natural gas tankless was, after the $600 ecoENERGY Residential Retrofit program were between $2,600 and $2,800, all in. We have not sought nor received an official quote for an electric tankless water heater (too busy with our other home renovations and energy conservation activities right now). However, from what I can find the units themselves cost under $1,000. Here’s a link to the SEISCO web store for their product pricing as an example of an electric tankless water heater.
The installation to me would have to be less as there is no special venting required. Depending on the manufacturer and model, one may or may not need an expanded electric panel. I found a web site called Go Tankless which has a detailed review of natural gas and electric tankless water heaters confirming my suspicions that installation costs for an electric tankless water heater is less than that for a natural gas model.
What about ongoing operating costs of a tankless water heater? Well, you will read about how it depends on the efficiency of the tankless unit, meaning how efficient the energy source is to heat the water. Natural gas units are generally said to be between 60 and 85 per cent energy efficient; that is only 60 to 85 percent of the natural gas used actually heats the water. Compare that to electric tankless units which are said to be in the 95 to 99 percent energy efficiency range; that is almost all of the electricity used by the unit goes to actually heating the water.
I think I understand that. But, to be honest I look at a different factor. What has been the price of natural gas in the recent past vs electricity and where are the costs of those two energy sources headed? This can be a regional specific issue. Here is an article from the Financial Post indicating that Natural Gas prices have doubled or more from late 2007 to June 2008, as well as one from the CBC on the same topic for Albertans. I tried but could not find a chart other than this one from the same Go Tankless link above showing their forecast of electricity and natural gas prices.
Lots to think about. No simple solution. My current direction is towards an electric tankless water heater even with no government incentives. More to follow.
To continue with the next article in this series on tankless water heaters, simply select this lini to Part 8.






































