The house I live in has an existing oil-based boiler for both heat and hot water. The hot water tank (50 gallons) will likely need to be replaced in the next few years as it is more than 10 years old, probably approaching 15. I am on well water without a water softener, and I assume that the previous owners never did any sort of maintenance with the current hot water tank. (A neighbor mentioned that there is some sacrificial part that can be replaced every so often to extend the life of the tank.)

I keep reading that the hybrid heat pump water heaters are incredibly efficient, and I hate having to burn oil during the warmer months just to heat my showers. My plumber tells me that it’s a really efficient system and that I should keep it intact as long as I can. He also seems a bit old school in his opinion and preferences, as he scoffs at the idea that I would eventually like to replace the whole boiler and system with a heat pump system instead.

Is there a good place to learn about how my existing system works, and any way to compare to possible savings (or pitfalls) of switching to a new system? Are there other options, such as tankless hot water heaters, that I should consider? I gather that recovery time with a hybrid heat pump water heater will be much slower than the existing system, so should I also calculate for a larger system (65 or 80 gallons)? Two adults live here full time but we frequently host guests and family gatherings, and we sometimes need enough hot water for 10 or so adults to shower. There are three full bathrooms in the house and one day we may add a fourth.

  • yesman@lemmy.world
    1·
    5 months ago

    (A neighbor mentioned that there is some sacrificial part that can be replaced every so often to extend the life of the tank.)

    It’s called a sacrificial annode. It’s purpose is to attract all the rust to it’self to prolong the life of the tank. They’re supposed to be replaced every 3years or so, even more frequently if you’ve hard watter.

    Most people don’t know and have never checked. If it’s been more than 5 years, it’s probably just a thin red mud at the bottom of the tank. (one of the reasons water is drawn from the top).

  • CompactFlax@discuss.tchncs.deEnglish
    0·
    5 months ago

    If you don’t live in a hot climate, many heat pump water heaters take heat from indoor air. Be aware of that - you’re heating air, then moving that heat into the water tank. It really drops efficiency. But they’re almost certainly a lot cheaper to run long term than paying for oil deliveries! They’re not necessarily cheaper than gas, because gas is just so cheap. I’d be wary of replacing a working system, because it’s probably not going to break even, but check for incentives that might help with the cost.

    If you make the investment, a water softener could be a good investment. Draining/flushing and maintaining the anode rod is a big factor in longevity.

    Tankless is ok, but it burns oil or you need pretty serious electric service. One downside is that the hot water piping doesn’t get the heat transfer from the tank of hot water so the whole pipe length cools fairly rapidly; 1hr between showers and you need to run the tap for a while.

    I believe that a heat pump boiler should have backup electric heating elements that kick in when there’s high demand or if it is too cold for the heat pump to keep up.

    • AA5B@lemmy.world
      1·
      1 month ago

      Yeah this is where I am. My water heater should have a few more years in it, but I’ve been gradually electrifying as things need to be replaced (stove, car, some heat), so what about the water heater?

      I don’t know if the heat pump would serve me well

      • electricity is expensive here
      • my teens take forever showers so recovery time is important
      • basement temps can fall into the 40’s in winter

      On the other hand my kids are in college so recovery time may not be longer matter

      • CompactFlax@discuss.tchncs.deEnglish
        2·
        1 month ago

        It will be colder in the basement if the heat pump heater is there, unless it has a separate condensing unit outside but they don’t seem to be the typical setup.

        HPWH usually have the same electrical hookup requirements as a conventional, so recovery isn’t typically a problem.

        Gas per kWh is cheaper, I bet.

  • David_Eight@lemmy.world
    0·
    5 months ago

    Heat pumps don’t work in freezing temps so replacing your entire system with a heat pump is a bad idea. Heat pumps are very efficient, so adding a heat pump to support your current system is a good idea.

    And your plumer is right about it being efficient, at least as far as hot water for showers etc. during cold months. I’m not so sure how efficient that is during hotter months so using a heat pump for hot water during hot months would be efficient though.

    Geothermal Heating is the most efficient but also the most expensive(15k-30k ish).

  • Brkdncr@lemmy.world
    0·
    5 months ago

    Pitfalls:

    You have a small space: heatpumps need airspace and it needs to circulate. An enclosed closet won’t work.

    Your heater is outside: heatpumps pull air through and dust/cobweb buildup isn’t good.

    You dont have electricity to the heater: heatpumps need a decent cuirruit size to run. Some can run off a small 120v circuit.

    You didn’t size right: heatpumps can’t keep up with sustained demand usage. A larger tank offsets this.

    You can keep your old system too though. Just put your hybrid before it and set your temps at like 125 for the heat pump and 120 for the boiler. Your boiler will rarely need to run unless you have sustained usage, a power failure, or it needs to bring temps up in the water it’s holding.