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, more 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. With a natural gas tankless water heater you are directly consuming a non-renewable resource.
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! And, the closer you place the hot water heater to the areas that use the hot water in the home, i.e bathrooms, kitcheds, etc., the less water that will be wasted travelling from the hot water unit to the faucet. 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.
11 responses so far ↓
1 A // Jul 3, 2008 at 12:53 pm
Do you watch Holmes on Homes? There’s a fourm on the fan site where the topic of tankless has come up a number of times and a quick search will lead you to more links.
Electricity vs Gas:
In Ont. Heating with Gas is cheaper than electricity (at the moment).
As for elect. being greener? Maybe, I believe nuclear is what supplies a good portion of Ont. elect. There are still coal and oil burning power plants out there as well. Solar/Wind power only supplies a very tiny portion of elec to the power grid.
Cost:
My guess is you’ll find it may not be that much cheaper. I haven’t looked at elec but for a whole house tankless, I’m thinking you’ll need one that runs at 240V and something like a 60A breaker. (Think: similar rquirements to an electric oven)
Efficiency:
Carefully with the numbers. Combustion of fuel for heat is never 100% whereas elecicity is always 100% (i.e. heatin element on a stove) but the part that matters is the transfer of the heat to the water. That’s where the design of the tankless unit comes into play.
BTW that site lists US only prices.
Flow VS temp rise:
Check these numbers carefully. Between the two. I seem to recall there is a difference.
Anyways, keep doing your research. Keep in mind that you can always find info to support the answer you want. If you want the “truth” be sure to research the counter-argument too.
Yes, I have the Rinnai tankless that you got quotes on. It wasn’t 100% planned so I never did all the looking and research you’ve done. I chose gas over elect because from a heating perspective Gas is cheaper the Elect. (for my region).
Good Luck!
Cheerio!
A
2 A // Jul 3, 2008 at 12:54 pm
PS. I should also add I dont’ have the venting issues you have.
3 Dan // Jul 3, 2008 at 1:19 pm
Hi again Al,
The challenge I am having is the easy way out is the ‘do nothing’ approach. Most people tend to take the easy way out until they are forced to change and then many times it’s too late.
The other challenge I have is that I am just an average home owner and I don’t understand all the numers flying around on water heater discussions.
For example, on another forum (not holmes on homes fan club) strong proponents like to use the arguement in the States that most electricity in the States is generated by Coal plants; thus no one should use an electric tankless because ‘chances’ are the electricity anyone’s electric tankless water heater consumes will indirectly generate more polluting stuff into the air. That type of generalization doesn’t sit well with me. Your point about how electricity is generated is more to the point.
As well, if I was 100% green I would not use air planes or drive any type of car and I would be financially bankrupt because I would have already installed solar panels sufficient to supply all of my home’s electricity needs, including solar water heating.
To me it’s a balance.
Another issue I am having is that everyone has an ‘opinion’, very few of which are volunteered with fact based studies by independent bodies. And, as an average home owner, my head spins in trying understand stuff like kilowatts, btu’s, ton’s of polluting emmissions (still can’t get my head around how a gas can be measured in tons…..many have tied to explain it to me but I’m a lost cause on that one
). No wonder most folks take the east way out and do nothing.
So, I’ll press on and look for supportable facts, including actually getting a quote in the next several weeks for an electric tankless to see what they say.
Most folks who have tankless seem to have natural gas and not electric. Not sure why other than a ‘follow the herd’ approach.
Tomorow I’ll write about, to try and present both sides as I see it, I found there is one electric tankless water heater that has some ‘credentials’ to it … even if I don’t understand it all. (yes, it is about one of our site’s advertisers).
Thanks for your comment.
Dan
4 NC // Jul 8, 2008 at 6:02 pm
Dan,
You say you are not technical, yet you assumed that the increased venting rqmts of the tankless unit mean that it must be emitting pollutants. This is not correct. The more elaborate venting is due to a) more throughtput due to the faster (but shorter) burn-rate, and b) use of outside air for combustion (sealed system) for safer operation & higher efficiency.
5 Dan // Jul 8, 2008 at 6:11 pm
Hi NC,
Well, I disagree. Any time natural gas is burned it is emmitting pollutants; not as much as oil, or gasoline or coal, but ennitting pollutants it is.
Even a natural gas hot water tank emmits pollutants causing venting being needed to the outside. In our current house, the current natural gas hot water tank required venting either up through the roof or with a power vent (i.e. fan) it is not being vented out the back of the house.
An electric hot water tank or electric tankless waer heater whose source is solar energy or wind or hydro electric or nuclear is not emmitting any pollutants.
Guess we disagree, sorry.
Dan
6 NC // Jul 9, 2008 at 12:24 pm
Dan - sorry I was not clear. Your quote: “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.” implied that you think a tankless natural gas heater pollutes more than a regular (tank) heater. That is the misconception I wanted to address. Of course burning methane, they both emit some CO2 (global warming pollutant) along with water vapor. By the way, nuclear electric power produces some “pollutants” that must be guarded for tens of thousands of years!
7 Dan // Jul 9, 2008 at 12:38 pm
Hi NC,
Thanks very much for the clarification. It is very much appreciated.
A agree with you (if I interpret your comments correctly) that nuclear power is not a personal favorite of mine either. No air pollutants, however one slip up and the environment ‘pollutants’ are horendous.
From my understanding (that is ever expanding in this strange new world [to me] of tankless water heaters) I agree that a natural gas tankless does not pollute more than a natural gas hot water tank.
It does concern me (and it could be just my personal bias) that a natural gas tankless requires that special venting. It is the need for that special venting which makes a natural gas tankless not as usable for a retrofit as say an electric tankless.
Why? It is prescisely because of the special venting. In fact, the second salesman who tried to sell us the Rinnai natural gas tankless water heater initially told us that he coulldn’t put one in our basement because of it’s configuration. It was only when I pointed out what the first salesman’s approach was that he said then that it could. He told me that he see’s less than 50% of the existing homes he visits on his sales calls that he can actually install a natural gas tankless because of their exising basement configuration prohibits the special venting needed.
So, that location in our house was a good 30 feet away from the incoming cold fresh water line which would have caused wasted water, wasted energy (of any type) heating the water as it travelled the extra 30 minutes to the tub, shower, etc. unless I paid even more money for additional devices said to help speed up that distance travelled.
On the other hand, from what I understand (and please point out if this is incorrect and where I can look to obtain more information) an electric tankless water heater can be installed anywhere….in a closet….under the stairs….and so on because it does not need any special venting. As long as a couple of electrical lines can be pulled from the electric panel you can install it anywhere that has access to the cold incoming water and the existing hot water pipes. Heck, you don’t even have to install an electric tankles water heater in the basement.
Thanks,
Dan
8 NC // Jul 11, 2008 at 2:25 pm
OK, I’ll share my personal experience w/ tankless units, which is quite recent, and not as constrained economically as the average project. We redid our 28-yr old, 2nd floor master bath as a ’spa’ w/ soaking tub & multiple-head shower. To handle the hot water demand, we put dual Rinnais in the attic above, where venting them though the roof was trivial. This did require a new 2-psi gas line and 1-inch water line to the attic, but those were not big cost items. We were also able to include a drainwater heat recovery system on the shower drain.
I never seriously considered electric tankless. Peak demand is a problem for electric utilities these days, but the gas company can easily handle the max demand of the Rinnais when they fire up. Also, at Energy Factor of 0.85 (essentially an efficiency measure), these natural gas units are a better use primary fuel than 95-99% electric units, when you consider the efficiencies of the power plants & transmission losses. Of course, as renewable sources of electricity become more prevalent, I might think otherwise - like converting the Rinnais to H2!
Anyway, enough on my house. I think your basement situation does make the 2-way (intake+outlet) venting required more difficult, although I do have a basement closed-combustion gas furnace that requires similar venting. Sometimes it depends on the creativity of the installer, within the code restrictions, of course! Electric is probably the way to go for you. Good luck.
9 Dan // Jul 11, 2008 at 2:35 pm
Hi NC,
Many thanks for sharing. Placing the Rinnai’s in the attic actually is quite unique. I had not heard of that installation approach previously.
I am jealous that you are using a DWHR device. I would like to as well. However, as explained in another article on our site our main vertical drain pipe into which the DWHR device would be placed is behind finished drywall in the basement. It is actually part of a 2 piece bathroom where on the other side of the finished drywall opposite the main drain pipe is the sink & cabinat! And to make the reno (if we were to do it, which we are not) more complex and time & $$ consuming, the prior owners of the house finished the ceiling of the 2 piece with …. yes, you guessed it ….drywall!
Just like Indiana Jones doesn’t like snakes, when it comes to finishing a basement ceiling “Drywall! I hate drywall [for basement ceilings]!
Lastly, totally agree on the relativity of electricity vs natural gas costs. In California my understanding is that electricity rates are much more dear than out hear in most parts of the east coast.
Many thanks again for your insites as one who has been there / done that!
Dan
10 Ginna // Jul 28, 2008 at 11:26 pm
Dan,
I’m curious as to why you only got quotes on the Rinnai. There are other models which allow for horizontal venting. (The Bosch comes to mind, is carried at Home Depot, and is much cheaper.)
I just had an audit in preparation for a big renovation, and both gas installers I’ve talked to think the Rinnai is seriously overpriced.
I’m leaning towards the Bosch with a DWHR system. The total cost will be less than $2500, and with the $530 back (including the DWHR unit), I’m doing pretty well.
BC Hydro (who have a vested interest in pushing electrical), recommend gas for tankless if possible:
http://www.bchydro.com/business/investigate/investigate831.html
In particular, the wiring and amperage requirements of the electrical may surprise you - they far exceed a standard tank model.
Electric models also have far lower temperature rise.
Those were factors in my decision anyway.
Cheers,
Ginna
11 Dan // Jul 29, 2008 at 2:24 am
Ginna,
Many thanks for this. I have so many thoughts that simply leaving a comment will not do. I will post both your comment and my thoughts in a separate posting on July 31st.
Dan
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