Tanks and no tanks

July 2 2009 by Ellen Roseman

I’m talking about hot water heating, a topic that ignited a blaze of controversy. Some people swore by tankless water heaters, a technology long used in Europe but new here. Others who replaced their hot water tank with an on-demand system wanted to rip it out of their home.

Some comments ended up in my blog post a few weeks ago, but more are coming in. It seems everyone has an opinion on how to save energy. It’s a subject that makes readers get really get hot under the collar.

Let’s pay tribute to Dan, a homeowner who shared his experience with others and came up with than 500 tips for saving energy, of which 275 cost absolutely nothing to do. You can find his tips broken down into subcategories here.

“Our objective is in part to remind people that they don’t need to wait for government handouts to reduce their household utility bills at any time of the year, as well as provide a quick list that people can access whenever they want at no cost,” he says. “After all, most of the items on the list were submitted to us free of charge.”

Let’s also give a shout to Jim Davidson’s book, which gave lots of advice about how to make your car go further before filling up the gas tank. Some of his 75 tips made people exceed the speed limit with indignation.

12 comments

  1. GG

    Jul 2 2009

    I had a tankless water heater installed in my house last August and we are at the point of going back to a conventional water heater.

    From day 1, there has been fluctuation in water temperature for the first 5 or 6 minutes, so that we don’t take the chance of going into the shower until we have basically wasted lots of water and gas.

    The water at some points goes from moderate to freezing to hot enough to almost scald you.

    Technicians from the company that installed it and the distributor have come to my house on 2 occasions and seen for themselves the problem. The person from the distributor has stated that the unit is functioning as it should, so tough luck for me.

    Anyway, my opinion to someone thinking of a tankless water heater would be – beware – you could be in for a large, expensive disappointment.

  2. RA

    Jul 2 2009

    I have been designing low energy, passive solar, environmentally sustainable, residential homes, renovation and additions for the past 25 or so years. I have seen it all two or three times, meaning how often I have seen the wheel reinvented.

    Tankless units can waste water. Let’s say you are the first one up in the morning and you need hot water, so you turn the hot water tap on. The unit in the basement senses the water flow and call for hot water and sparks to life.

    The first thing it does is turn the exhaust fan on and lets it run for 10 to 15 seconds to “purge” the chamber of any possible residual gas fumes (a safety feature to keep it from blowing up if there is).

    It then cycles the fan off and sets up to spark up again this time with the fan but also the gas burner. They are called instantaneous, but it still takes it a little time to come up to temperature and then bring the flowing water up to temperature.

    Then there is the usual wait for hot water to get up from the basement, as with a conventional hot water tank. Meanwhile, the water is running down the drain as this is happening.

    Secondly is limited gallon per minute flow. You can oversize the unit, which would make it less efficient, but if properly sized it can only instantaneously heat 2 to 3 gallons per minute. Oversizing might give you 4 to 5 gpm, but then it would be wasting energy.

    A typical shower takes 2.5 gpm, which, if the unit is properly sized, means you can’t be, for example, doing a load of laundry or dishes at the same time, let alone also thinking about using the tankless unit to do space heating as well. I have heard of complaints of this where the cure is to install a storage tank.

    Thirdly is cycling (I only heard of and realized this a few days ago). If you have a single lever tap, meaning a tap with one lever that you swing from side to side for hot and cold water, and you are rinsing vegetables, a glass, brushing your teeth, or doing whatever where you need a little shot of water and you have the lever set for mostly cool water, because it is a single lever there will be a little bit of water flow from the hot side which would be enough to spark the unit to life. The instantaneous water heater is triggered by water flow.

    This one doesn’t affect you as much. What do you care if the unit is cycling on and off and on and off and on and off, etc., unless it shortens its life span? I haven’t seen any statistics on this.

    Just some thoughts.

  3. AW

    Jul 2 2009

    Tankless lasts at least 2 to 3 times longer than tank

    Tankless warranties are probably double that of a tank, on average.

    How much is that extra space worth to you? Ask your friendly neighbourhood builder what 16 square feet of living space is worth.

    You get a $315 rebate from NRCan for tankless (EcoEnergy); $315 rebate from Province of Ontario for tankless (EcoEnergy); and a $300 rebate from Enbridge.

    Also, a $3,000 tankless installed would receive a $300 tax credit, thanks to the new Home Renovation Tax Credit Program from the government.

    That’s a good $1,230 in rebates! It would make a tankless more cost effective than almost any tank out there! Renting? $33 a month vs. $22 or so for a power vent, or even $12 or so for conventional.

    The rebates are like getting 37 months of free rent!!!! Or over 3 years! How’s that for payback or even better, return on investment?

  4. KM

    Jul 2 2009

    In my home, the decision to install a tankless hot water system was accelerated due to an existing leaky tank, but I would encourage others to consider dumping their hefty water tank rental fees in order to take advantage of the exceptional tax breaks and Federal and Provincial grants currently available for this home upgrade.

    It seems to me that the rebates and energy saving numbers produce a conservative 3-year payback in my case (avoiding buying a 40 gallon tank), and probably less than a 5-year payback for those who decide to escape the clutches of their water tank rental company.

    I don’t see our family offsetting energy savings by using more hot water, simply because this device provides unlimited supply.

    PS: The unit we purchased comes with a 12-year warranty on the heat exchanger and while it’s almost maintenance free, there is some periodic maintenance required for lime build-up (less so in our Toronto area water supply). This, however, is not a complicated process for a homeowner to manage personally, if he or she is so inclined.

  5. brad

    Jul 3 2009

    On the subject of energy efficiency (not necessarily tankless heaters), it’s worth noting that in these times of low interest rates an investment in energy efficiency improvements can provide very impressive returns — on average 16 percent and as high as 41 percent, which is hard to come by even in the stock market unless you’re really lucky.

    This rather ancient graphic is way out of date in terms of stock market returns, but the paybacks for energy efficiency investments are still valid:

    http://hes.lbl.gov/hes/profitable.html

    You shell out some money up front for the energy efficiency improvements (e.g., efficient lights, efficient fridge, efficient washer, whatever), but the money you save in energy costs pays for the difference within a few years and from then on it’s clear profit.

    The key is to make these decisions at the time you’re going to have to replace your equipment anyway.

    If you just bought a new fridge last year you won’t save money by replacing it with an Energy Star model this year. But if you have a 20-year-old fridge that’s busted and you need a new one, spending a little more up front to buy an efficient model becomes an investment as your energy bills go down.

    Furthermore, if you take your energy bill savings and invest them, your gains are even higher.

  6. Dan

    Jul 4 2009

    We evaluated Sears and EnerWise over a year ago for a Rinnai natural gas tankless water heater.

    We decided that, even after the ecoENERGY Residential Retrofit program’s rebates (one from the Feds and the matching one from the Province), that our financial payback was still around 8 years.

    With the warranty on the unit only 5 years, I wasn’t willing to take that risk.

    Dan

  7. Joren

    Jul 5 2009

    I have had two homes with tankless water heaters (both Luna Baxi but different models) and the difference is night and day. Both units are “combination boilers” meaning they heat water for domestic use, as well as to heat the home.

    Note that these systems had domestic hot water as the priority. If you are having a shower and the heat kicks on, the unit will not heat water for the house heating – you will always have hot water for showers, dishes as the priority.

    First off, if anyone is considering tankless, I would strongly recommend that you avoid Baxi, and stick with a more popular name like Rinnai (made in Japan). I lived in Japan for a number of years and Rinnai is all over. Mine worked great! From my experience, I’m told that because our climate gets SO cold here in Canada, that the temperature rise in units popular in Europe or other “warmer” climates is not sufficient. My experience would appear to back that up.

    First home: yes, it takes a while for the hot water to reach you. Could not take a bath in winter as the rise in temperature was not sufficient to heat the water to the degree I wanted it and last until the tub was sufficiently filled. So it was showers from then on. When mine went on the fritz, it was difficult to find a technician that was familiar with this brand – then it was harder getting parts for it.

    Second home – as I mentioned – also a Baxi (which almost killed the deal on the home purchase) but the model is newer and seems to work much better. I am able to have a bath (but don’t much as now I’m trying to conserve water) and yes, it still takes a few minutes for the hot water to reach the tap, but I’m not paying to heat water 24/7. (Plus which, as I live in a townhouse downtown Toronto, there isn’t room for a traditional hot water tank anyway.

    I like the idea of a tankless. I’d choose a Rinnai anyday, and make sure that it is sized correctly for your existing and possible needs.

    One bonus I really like is that because the tankless heater operates on about 100w of energy, if theres a power failure, I can plug it into my portable battery pack and still have hot water for showers. Not that that happens often, but it does happen.

  8. Traciatim

    Jul 28 2009

    I think an ideal setup is a solar heated pre-heat system, a larger ‘whole house’ style electric hot water heating system, and then smaller point of use systems that are electronically controlled to output the proper temperature.

    Since many electric hot water heating systems have trouble with flow rates, especially in cases where multiple faucets are being used, then the solar pre-heater will help.

    Also, on important items like your dishwasher and showers, you could have smaller booster heaters for each point of use or each room.

    Though expensive to set up, this would probably give you unlimited hot water in almost every application.

    Though on the other hand, since Canadians heat their homes from about Sept. 1 to June 30 of the next year, all that ‘wasted’ hot water tank heat just leaks in to your house anyway.

    So why bother caring and work on home insulation/windows/air-sealing instead.

  9. Gord

    Feb 22 2012

    I live in a townhouse condo and have a Baxi Luna combo heater, which works half the time. I am constantly having to activate the unit manually to get hot water by either resetting the system or tricking it into heating the house.

    Taking a bath is out of the question because after a prolonged period of heating water the unit trips and shuts off automatically.

    In the summer, when I am using hot water and the AC kicks on hot air comes blasting out. The hot air heats the cold instead. I actually think that this is due to a faulty toggle that isn’t turning off the furnace when the hot water is activated.

    Even though I don’t see the gas bill, I don’t believe that there are savings from the tankless combo.

  10. Cat

    Mar 10 2012

    I have a Baxi Luna 310Fi. Most of our 27 apartments have problems. Baxi is the worst. It cost me $2,400 to fix mine. A new one is about $2,600. My neighbor already spent over $1,000, still working on the problem. Don’t get tankless boiler for tenants. You will get complains all the time. I’m looking into switch to an old fashion tank boiler. Baxi sucks. Their tech supports are useless. Don’t get Baxi.