Water and Water Heat

thz.ca, Costs, Electrical, Geothermal, Water Heat, Insulation, Landscaping, Roof, Windows, Deck

    2012,   2011,   2010,   2009,   2008,   2007,   2006,   2005

Here's what's on this page:

  • The solar ready water heater gives up
  • New dip tubes for the water tank to extend the amount of useful hot water
  • A hot water meter to monitor use of hot water to see if solar hot water makes sense
  • Added another 3 litre toilet
  • A leak in the "solar ready" hot water tank
  • Remove tankless unit and install a "solar ready" hot water tank
  • Installation of a tankless on-demand hot water heater


Well, the hot water heater saga has finally ended. The solar ready tank that I had rusted through in less than 4 years. I took the tank apart to look and found that it was a really cheaply built tank. The biggest problem though was that it did not have an anode to protect it from rust. Since we had put the tank in we had noticed some rusty water from time to time. Now we knew where it was coming from. That tank was just a piece of junk.

The hot water meter is now giving us a better estimate of how much hot water we use. Our average use is just 19 US gallons a day (about half a tank) or 72 litres a day. Far below what the solar hot water people estimate. Averaged over a month our high use is 25 gallons a day and our low use is 15 gallons a day. These are averages at this point. If I start looking at solar hot water again I will do a daily track of use for a couple of months before I decide on the required capacity.

The other aspect of the hot water tank is the electrical use. Over the first 14 months of use the average electrical use was 171 kWh per month for a cost of about $12/month in power (at 7 cents kWh). That's about 30 kWh better per month than the old solar tank running electrically. Yes I know - I should have gone with the basic electrical tank first!

Here's the leak. Right beside the same nipple that leaked the first time. The pick is showing where the tank has rusted completely through. This perforation is very small but since the first leak at this nipple I had put some wick material in here to detect any future problems. When the wick material became damp I opened up the cover to look.

Curiously the seal I made on this nipple with water epoxy and a new rubber gasket worked fine. It was the shell of the tank that let go. Shows you what happens when you run a tank without an anode.

Sometimes my wife says I get a little carried away with projects. The thing is there is rarely a lot of room in our house, and I have a lot of stuff that I need to complete a project. Here is the new water tank getting ready for installation. I've got my electrical tool box, my plumbing tool box, and various other parts and pieces to put this all together.

Note carpets on floors and counters to protect surfaces. The fan on the floor is used to dry out the working area as there is inevitably some water spilled there.

So here is the final water tank. A basic 40 gallon electric tank. I found it at Canadian Tire. Since everyone in our area uses gas water tanks this one had been sitting around for years. They gave it to me for $199. I should have gone with the simple electric tank first! It even had installation instructions that I could understand.


2009 is a year to make some small improvements to our water use. The water tank wasn't producing enough hot water to fill our bathtub so I added some angled tubes. Then I added a water meter to the hot water tank to try and make sense out of how much hot water we use. All the solar panel people were giving me "estimates" of how much water we needed and they all sounded much too high for the way we use water. Putting in a meter will sort out that uncertainty in a very short time. Finally I found a 3 litre toilet on sale at Canadian Tire just before Christmas. I bought it and added it to our house later in the winter.

Our water tank has all the fittings on the side. The cold water inlet and the hot water outlet are about 12 inches from the bottom and the top of the tank respectively. When we tried to fill our bathtub we found that we ran out of hot water before the tub was full. We had also had some trouble with rust in our water if the tank was left idle for any length of time. To try and solve both these problems I added stainless steel angled tubes. These tubes extend the capacity of the tank by about 6 inches on the top and the bottom. We now have no trouble filling a tub. The stainless steel tubes and fittings also do not rust as much as the galvanized pipe ends we had there previously.

One of the main problems when you change your lifestyle to live more efficently is that the general averages no longer apply. Whenever contractors try to size a system they often use averages and "rules of thumb" for setting a system size. I was convinced that we didn't use anywhere near the hot water that the contractor's averages were showing. In order to properly size our hot water system I decided to add a hot water meter. This meter is designed to read the amount of hot water that a house uses. It is rated so that you can mount it on the hot water outlet but I put in on the inlet side. So far we are only using about 1/2 of the hot water that a "normal household" would use. We'll collect the data for a year or so and see how we use this resource.

Eventually there comes a time when pricing catches up with technology. This 3 litre toilet was on sale for $172 so I bought it right away. The 3 litre flush only works for pee but a 6 litre flush handles the messy stuff. This toilet keeps quite a bit of water in the bowl so while that reduces the flush effectiveness, you end up not having to clean it as often. Our other 3 litre toilet (our main one in the basement) has a very small amount of water in the trap and needs more frequent cleaning but will flush almost anything with only 3 litres.


Well, I said before that at least I liked the hot water tank even if the installers had done a poor job. Well this summer the tank let us down. It started to leak around a 2" tank nipple on the side. When I drained the tank and took a look I found that the nipple, which is part of the casting, had been damaged. Someone had put a little bit of caulking in the damaged area and then screwed the nut onto the nipple. The caulking had deteriorated and the leak had started. I'm not sure if this cover up to the damaged casting was done at the factory or by the installer. I suspect it was done right at the factory. So I'm not too impressed with this tank now.

The chip in the casting was in an area that formed a seat for one of the temperature sensors. I fixed the seat with potable water grade epoxy. Then I built a backup seal in the threads on top of the sensor. It now had two seals. Hopefully one or both will be sufficient.

Now I'm not very confident in this tank. That chipped seat can't really be fixed and epoxy is not likely going to be a long term solution. Whether I go ahead with the solar collectors for a tank I am unsure of is up in the air right now.

On the up side, electric hot water is only costing about $14/month for energy. That's right in line with the tankless hot water heater but I'm one step closer to getting rid of gas from the house. We now only use 0.3 gigajoules of gas a month. The gas company called and said they wanted to replace our defective meter. Took a lot of explaining to convince them that our meter was fine and that I really am only using a gigajoule every three months.


OK, the tankless water heater was a complete bust. First, water heat is a really small use for gas, less than 2.5 gigajoules a month. That means that running a gas water heater costs only $14 for gas but $30 in service charges. The best thing to do is to get rid of all gas appliances and disconnect the gas from the house. The second problem was that the tankless water heater is a 100,000 BTU gas appliance. If you have more than a 50,000 BTU gas appliance then you need combustion make-up air supplied to the house. This is a 5" duct that brings in cold air which defeats the purpose of draft sealing. The tankless water heater just didn't work in our house layout. It took over 30 seconds to get hot water to the furthest tap. The house is designed for a central water tank and the runs of piping are too long for a tankless unit. The piping runs for a tankless unit need to be really short.

Finally, the operation of this unit didn't work for us. Although the unit operated as specified it was very difficult to mix water to get warm water. The unit needed 1.2 US gallons a minute to switch on. I had put low flow aerators and shower nozzles throughout the house (we have a very low water consumption level). I had to take all the aerators off the taps and put in high flow shower heads just to make warm water. But when we put in high flow shower heads we got condensation on the bathroom walls, and our water use went up 50%.

Then in the peak of the summer - the final straw - when temperature of the incoming water to our house went up the tankless unit would shut off with even the slightest amount of cold water from the cold tap. We couldn't even take a shower. That was it. The tankless had to go. It wasn't giving us reliable hot water and the requirement for combustion make-up air was holding up our final permits.

So I decided to go with an electric tank water heater. But I wanted some options in the future. I settled on a solar hot water tank with an electric backup. The solar tank is well insulated and has two heating loops in it, one for solar heating, and one where I could hook up a desuperheater from my heat pump (apparently it is possible to retrofit one). I contacted the City and the change from gas to electric closed off my open permit for the gas tankless water heater (in noncompliance due to no make-up combustion air). As soon as I got the electric tank installed I was able to call the inspector and get my heating permit signed off.

It was too expensive to hook up solar collectors at the time I installed the tank. I'll run the tank on electric only for a year or two to get a indication of how much energy it takes. Then when I hook up solar collectors I'll have a really good idea of what the savings are.

Here is the new solar hot water tank. I had to move the geothermal electrical panel over to the right as far as it would go. The installers didn't do a particularly good job on the installation. The pipes were crooked, they used pipe dope instead of teflon tape on the fittings, and the electrical wasn't that great. I liked the size of the tank and I liked that there were two loops for future heating services. I just thought that it could have been installed better.

The plan is that when I put solar collectors on the roof I will run the pipes up the chimney. The chimney goes right up to the roof where I want to put the collectors.

Here's the final electrical. I took the original installation down and rebuilt it on a piece of plywood in my garage. I took my time and did all the wiring a lot more carefully than the installer. I also added the check meter and another small breaker box to control this important unit. I also changed the relay box for a bigger one (large grey box below breaker panel) so that the cover could be safely closed (the first one was too small).

I wasn't too keen on the plumbing job either. They used copper unions to connect the tank. The tank is cast iron and should be isolated from copper piping with dielectric unions (shown). I refit the connections with dielectric unions. The tank nipples here are only 1/2" and I can't find plastic lined steel pipe to use on this important connection. Right now I'm using galvanized pipe. I've found 1/2" plastic lined steel pipe on line but have had a hard time special ordering it.

Finally I insulated all the lines to and from the tank. I used two layers of foam pipe wrap to insulate these well.

All the instructions for the solar hot water tank controller have been translated from chinese. Here is an example. My favorite is the wiring colours on the top; black, chalkiness, and gules. The chalkiness colour is the white wire. The gules wire was green. The translations may be a little wonky but I can mostly make out what they are trying to say. I think I may change the controller when I get solar collectors. For now it is working fine.


One of the things your Geothermal salesperson will talk to you about is water heat. Geothermal heaters can produce hot water as an offshoot of the Geothermal heating process. There are two types of add-ons to Geothermal heat; demand hot water, and a desuperheater. The desuperheater is a gadget that makes hot water whenever the Geothermal heater is running. At all other times it needs an electric hot water tank. Demand hot water uses a second compressor to make hot water when it is needed. We looked at both of these options and felt they were too expensive. To add demand hot water to our Geothermal unit would have cost almost $6,000 more. A desuperheater was another $3000 but would rely on electric heat for half the year when the Geothermal unit wasn't running. I wanted more efficient, but not quite at that price.

I looked at a couple of options and settled on a tankless water heater. This is something I was familiar with from when I lived in Germany, but is not common in Canada yet. The heater only turns on when a hot water tap is opened. The burner lights up and you get hot water in the unit in seconds. It still takes some time to get the water to the tap, but it seems its only another 10 or 15 seconds longer than the old heater. In my initial calculations it looked like this unit will pay for itself in about 10 years. So we went ahead and installed a tankless hot water heater.

Here's the 20 year old gas water heater. It lives behind sliding doors just off the basement bathroom. With the sliding doors closed you don't realize there is a utility room there until the furnace comes on.

The new water heater is what's called a direct vent type. That means it vents directly through a wall to the outside. It has a fan that blows the exhaust air out the vent. In order to get that exhaust through the wall we needed to locate a spot on the wall where we could drill a hole. Fortunately you can vent these close to your own sidewalk and we had room on the west side of the house. Here is the sidewalk.

Then you hire someone to cut a hole in the concrete. The actual vent is designed to go through wood frame construction so it is 8" in diameter with a 4" vent pipe in the middle. Cutting an 8" hole through a solid concrete wall is complete overkill but that's what the inspectors wanted. Here is our contractor cutting the hole.

And here is the finished vent on the outside of the house. Don't let that big vent hood fool you, there is only a 4" vent underneath that big cowling.

Inside you can see the holes around the outside of the vent hood that would keep it cool if it were in a wood structure. Here it is in concrete so the holes are useless. Since the vent is pressurized you have to seal all the joints with a high temperature silicone caulking. The water heater manufacturer recommended that we use stainless steel pipe (which would have run about $500 for this) but put a tube of the high temp caulking in the box that allowed us to use 26 guage galvanized pipe for $30. Really poor instructions on this part of the installation - a sales job for something we didn't need.

Here is the unit. We got a bit of a runaround on the venting, and a tray on the bottom of the unit doesn't fit (an e-mail inquiry has not been answered two months later).

With this unit venting directly to the outside of the house and the gas furnace now replaced with a Geothermal unit the chimney is now abandoned. Since the chimney was starting to crumble in places this is another big fix we have avoided. We are going to cap the chimney to keep water out and then it shouldn't deteriorate any further.

And there we are complete. I actually mounted the water heater on the chimney so it is out of the way. Once the sliding doors are back on the utility room these units will also vanish from sight. You'll hear the hot water heater or the Geothermal unit come on if you are in the bathroom but otherwise you will not know there is a utility room there.

One last note. Although the water heater works really well, it is best if it is built into a new house where there are very short runs to the water outlets. It doesn't heat water very well for our low water use dishwasher so that has to heat electrically. It also doesn't heat water particularly well for clothes washing due to the distance the water has to travel (not a big deal as we normally wash in cold water). What is does really well is provide unlimited showers. You never need worry about running out of hot water, even if two or three people take showers in a row.

Then we had our biggest disappointment. On our next bill we expected a much lower gas bill. We had calculated our gas savings using on-line calculators and other tools that figured costs using the price of gas. What we had forgotten was the delivery charges. In our de-regulated environment the cost of gas is billed separately from the delivery charges. We had not been using the delivery charges in our calculations. If we had done that we would have immediately realized best savings happen when you completely remove a utility. We now use less than $17 of gas a month, but it cost over $27 to have it delivered. That means that we will be paying more than double the cost for gas for our stove, hot water heater, and dryer. That's $324 a year for gas delivery. I'm pretty sure that would have changed my calculations and led me to one of the Geothermal options.

So in the end I've got novelty but not the economics I was hoping for. Oh well. You can't figure out everything perfectly. I'll just enjoy a long shower...

thz.ca, Costs, Electrical, Geothermal, Water Heat, Insulation, Landscaping, Roof, Windows, Deck