When my partner and I moved from Toronto, Canada to Oxford, England we found the strangest feature in our new little flat. Our only closet was filled by a 125 litre hot water tank – the size usually found in the basement of a North American house.
During our winter rants, when it became a challenge to keep the tank warm as the latest technology was to wrap it in a type of foam PVC jacket (both toxic and ineffective), my partner educated me on her experience with water heaters in Brazil. She used a heater technology called point-of-use (POU), which is a tankless type water heater located next to where the hot water is wanted. POUs can run on either electricity or gas. Whenever she needed to take a shower or get hot water in the bathroom, she flipped on a switch that was connected to a small heater in the bathroom itself – similar to the idea of turning on a kettle to boil only the amount of water you want to use.
We imagined how much water would be saved if we didn’t have to wait for the shower to get warm. Less piping would be needed along with this ancient heating technology similar to the giant, room-sized computer. We could use so much less energy, money and material to get what we want better than we had it. It would take up less space in our home and reduce the risk of water damage from a tank failure or rupture. An entire tank would not keep water hot all day just in case we needed it.
But I researched arguments against these clever POU tankless water heaters and found some interesting information. First of all, start-up costs are high because retrofitting a home that isn’t installed with a POU requires evolving the electrical wiring and piping. However, the POU offers long-term energy savings. A traditional storage water heater, like the one we found in our closet in Toronto, keeps water warm all day regardless of whether it will be used. This can become a huge energy/money drain for a household, and multiplied many times over for entire cities. Meanwhile the POU is small and efficient.
Second, POU users may have to wait a few seconds before receiving the warm water because it does need to be heated. This may be no different than turning on the shower and waiting for the cold water to become warm – except, with a POU, no water would be wasted.
Lastly, depending on the POU heater model, cold water gaps may occur when the hot water runs out. But this can be regulated with the water flow. By creating a water pressure system that isn’t bursting out water and is instead a steady flow, we can reduce the amount of water used per shower. When I left Canada, buying new shower heads with flow regulators was the latest eco-trend in saving water. The POU heater would perform two jobs at once by regulating flow and minimizing water consumption.
If I were to design a new home or renovate existing piping, POU tankless water heaters is an innovation I’d start with to get what I want and tread lightly on our planet. Dishes would get washed and I’d have a closet filled with clothes, not water.
Post by Dinesh Ram.