Thursday, March 29, 2007

Lets go Tankless.

In a zero energy home (ZEH), it pays to look for every little energy waster you can find. And you especially want to get to use every kilowatt hour you pay for, that's just plain sense. So, what's an energy waster we find in most houses? A water heater.

Water heaters heat water. (?) No doubt. But it's what else they heat that gives us cause for concern. If you own a gas or electric tank style water heater, you are heating water even when you are not using it. And that heated water is heating it's tank, and the tank is heating the closet it is in, and if it's a gas water heater, some of your heat is going up the flue. So, that's waste number 1. Secondly, if you are using a gas water heater, your efficiency is limited by the amount of heat that the water is unable to extract from the combustion products because of simple thermodynamics. Heat flows toward cold, the less cold the cold is, the less heat will flow there. So, heated water is inefficient to heat further, and that goes for anything above freezing. In fact, your standard gas fired tanked water heater is about 85% efficient while your high end (read expensive) flue gas condensing unit tops out at about 95%.

Enter the SEISCO electric tankless water heater. Its internals are made of thermoplastic so more of the heat made by the heater stays in the water. Actually, more than 99% of it. Yes, that's more than 99% efficiency. A sustainable liver's dream. It easily beats out electric water heaters on operational cost, and it beats standard gas units as well. High efficiency gas tanked and tankless heaters are close on the horizon and indeed, it has surpassed some of them in some areas with especially high gas prices.

The real goodie with this thing is its ability to be mounted almost anywhere. It is less than 16 inches square, and only 6 1/4 inches thick. Do you have six inches behind your fridge? I'm planning on putting mine behind the bathroom door. In the future ultra ZEH, I plan on using smaller units, about half the size of the one to the right, for several purposes. One will be used as a backup heater for the radiant floor heating solar combined system which will only heat the water to 90 degrees, and then the rest will be used in the rooms where hot water is needed, the bathrooms and kitchen. That way, the first one will only need to heat the water the few degrees needed to warm the floor, and the rest will only need to heat an additional 20 or 30 degrees for usage on site. Plus when the solar heater is doing it's job, such as in all the time except for deep winter, the electric units won't be needed at all.

As you can see, the benefits of a tankless water heater are many, and an electric tankless more than gas. I guess I didn't even need to mention the main selling point. Infinite hot water.


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