Re: Tankless water heater question
Really, it depends on the electric and gas utility rates where you live. In the northeastern states, electricity is considerably more expensive than gas. In parts of the northwest, electricity will be cheaper than gas. My brother who lives in Clatskanie, Oregon heats his entire house with electricity (and not a heat pump, either) because it's far cheaper than any other energy source available to him. (Clatskanie has among the lowest electric rates in the nation.)
Originally Posted by CincyDave
That said, the total energy usage of an on-demand water heater will be lower than a storage-type water heater, because the storage heater will expend energy keeping the water warm even when it's not being used whereas the demand heater will not. Further, an electric on-demand water heater will use less total energy than a similar gas unit due to flue losses with the gas. But that's total energy, not total cost. You need to compare the cost per standard unit of energy to understand the actual cost of operation. Don't judge by the EnergyGuide label, because those are based on average costs of energy, not the actual cost in your area, so they may not present an accurate comparison between the operating cost of electric vs. gas.
I have to concur with keith3267. One major reason that electric companies provide energy efficiency credits, besides government mandates, is that it's cheaper to pay for efficiency than build new power plants. However, while on-demand electric water heaters may be more efficient over a long period of time, their peak energy demand (how many watts they need at any given time) is much higher than for a storage-tank type water heater. Power plants, substations, and lines must be built to accommodate peak demand rather than average demand. That means if everyone switched to on-demand electric water heaters, utilities would have to build more power plants even though the total fuel consumption of those plants may be less.
Even natural gas facilities could be impacted by the use of on-demand water heaters (though I do not know to what degree). You can only force so much gas through a pipe; compressors can only pump so much gas into the system.
As for solar and wind power sources, those cannot be relied upon as the sole energy source (at least not until we can build high-density, efficient electric batteries) because they are weather dependent. It doesn't matter how much wind and solar facilities you have, you still need to build traditional hydro- or fuel-powered facilities to meet the demand during times of insufficient wind or sun. With a large enough power grid you may be able to generate some of the demand all the time, and all of the demand some of the time, but you'll never be able to generate all of the demand all of the time with only solar and wind.
The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.