Best HWH option?

leo95se

Hi folks! New member here and excited I found this forum.  

Just moved into a new house and am learning it while seeking upgrade paths.  

My first one is the hot water heater.  

I have a direct fired oil furnace, and oil fired hwh.  I have propane on-site as well. 

While I assume the oil heater is efficient I’m turned off by needing an annual contract for the burner. (At $300+ a year!)
any recommendations for best and most efficient option? Hybrid electric sounds enticing but all I’ve researched points to snake oil.  Other options- electric (expensive?) propane (less efficient?), instant/on demand with any of the above sources.  

Looking for practical application experience.  

Thanks!

Jamie Hall

Well, I expect that if you ask any five of us you will get seven different opinions, depending on the phase of the moon...

I will give you my opinion (singular) right up front: keep the oil fired boiler and hot water heater until they die, and get the service contract from you oil dealer, and get your oil from them too -- most good ones offer automatic delivery and many offer a lower price pre-buy option for the oil. This opinion is not just whimsy; all three of the buildings I maintain have exactly that combination, and it has turned out to be the most satisfactory and least hassle option. They do need maintenance, but everything does.

Now. First, let's assume that both your boiler and water heater are in decent condition (you should have them cleaned and serviced). Until they die -- which. like all machines, they will sooner or later -- there is no point to changing them out. That will cost you money which you won't save on the latest whizziest choice.

But sooner or later... In most areas, propane is a non-starter, as it is almost always going to cost more per BTU than oil. Sometimes a LOT more (a few areas, mostly agricultural, this isn't always so, and worth checking; if you have propane on-site for an industrial process or a major agricultural process, such as corn drying, it may be comparable in cost to the oil). Straight electric is also likely to be a good deal more expensive than either oil or propane, but that depends very much on where you are. Electric rates vary by a factor of at least 10, depending on location, and there are places where straight electric boilers and hot water heaters are competitive. You have to do the math on that. There are also places where air to water heat pumps for space heating are quite usable, and they use enough less electricity to be much more competitive. However. Despite rosy claims to the contrary, I have not seen any evidence that they are satisfactory if the design temperature drops below about 10 F. Not to say they don't work -- some of the top end units do -- but they don't appear to work well. I have heard mixed reviews on hybrid domestic water heaters, and the one that was installed in one of the buildings I maintained was a maintenance nightmare. Not that it didn't work. It did, most of the time, and at least one major resort with which I am familiar uses them (they have a bank of ten of them) quite successfully, but they have even slower recovery than straight electric, and so you need a large capacity unit -- and they do need maintenance, so you will need to have a good relationship with the installer. I myself am not keen on on-demand tankless units for domestic hot water, although they are a very good fit for one, or one and a half, bath applications. That would almost have to be propane, unless you have a very large electrical system (they take a lot of power).

For my money, when and if you have to replace either the boiler or the water heater, I would stay with oil, but possibly shift the domestic hot water to an indirect hot water heater, using hot water from the oil boiler as the source.

hot_rod

Do you have an oil furnace or oil fired boiler?
Where is the equipment located? The heat pump water heaters pull heat from the room where they are located, so a basement room as opposed to a closet in the living space would be best.   

Check for any rebates in heat pump water heaters, that could make the $$ part of the decision. The HPWH would not need a yearly service like the oil fired one. $300.00 pays for most folks DHW needs go a year.

www.dsireusa.org shows incentives in locations across the US.

www.coalpail.com has a good fuel cost comparison spreadsheet to plug in your actual costs.

oil tank in good shape?

ethicalpaul

Hybrid water heaters are certainly not snake oil. I installed my own a couple years ago and it has been providing hot water dirt cheap ever since. New Jersey even paid me cash to install it.

Why anyone would want to keep a boiler fired up all summer just to make some hot water is completely beyond me.

Larry Weingarten

Hi @leo95se , You've been given good info and advice. If you can let us know your location/climate, I think we can help you narrow down what will be a good fit for your situation. Also, having an idea how much hot water you use and what possible efficiency and heat capture upgrades might be done, can play into the mix, so you don't wind up with oversized equipment. Finally, are you a technical sort who is comfortable messing with equipment, or would you rather leave that to others?

Yours, Larry

JakeCK

I installed a heat pump water heater about 3 months ago. Allowed me to eliminate one flue and a gas line. It does use about 200 kWh a month to supply me with hot water, and it does take longer to recovery but I've been happy with it even with a family of four. Bonus points if you have PV solar. There is also the reduced possibilty of CO poisoning. It'll also help with cooling and dehumidifying in the summer months. 

Personally when I replumb my boiler I'm going to add a buffer tank and will opt for a reverse indirect buffer tank so in the winter I can switch over to dhw from that and feed the heat pumps tank with it. When I shut down the boiler in the spring I'll be back on the heat pump. Ultimately the heat for the HPWH comes from the boiler anyways in the winter. I'd imagine this would be the most efficient since it will involved one less energy conversion.

leo95se

Hi all 
excellent info, thanks!
I live in CT, and have a direct fired forced air furnace which is my AC source in the summer as well.  So it seems the indirect hwh thing wouldn’t work in this case?

I’m ok tinkering on my own with things for sure.  

Having been in the house for a month I don’t have a strong sense of use yet, but am burning approx 9.5 gals a day of oil (it’s been cold!) and no water bill yet.  

leo95se

hot_rod said:

Do you have an oil furnace or oil fired boiler?
Where is the equipment located? The heat pump water heaters pull heat from the room where they are located, so a basement room as opposed to a closet in the living space would be best.   

Check for any rebates in heat pump water heaters, that could make the $$ part of the decision. The HPWH would not need a yearly service like the oil fired one. $300.00 pays for most folks DHW needs go a year.

www.dsireusa.org shows incentives in locations across the US.

www.coalpail.com has a good fuel cost comparison spreadsheet to plug in your actual costs.

oil tank in good shape?

Tank is great yes. 330 gals. Furnace is 2015 and hwh is 2019.  The $329/year hwh service contract is Shay kills me. Everything is in my basement.  Only short term harm is if the hphw pulls that much ambient I’m taking away heating from the partially finished area of the basement.  

EBEBRATT-Ed

Not saying the service contract price isn't anything. But look at labor costs. Electricians & Plumbers are well over $$$/hour.

If someone told you you could by a service contract for your car for $$$/years it would be a bargen

hot_rod

Are you on a well, or city water?  Well water stays fairly consistent around 50 F. Public water, when stored above ground can get much colder, down into the 30’s in cold areas. So performance of any water heater depends a lot on incoming temperature
Performance ratings are usually based on 70 or 77 degree temperature rise

 crunch the numbers, I suspect the HPWH will be the least expensive to run and maintain. Even without rebates 

Your equipment is not all that old, might just run with it

rick in Alaska

If you are burning 9.5 gallons per day, you either have a huge house or no insulation. On a bad month with my 2400 square foot house in Alaska, I might burn as much as 2 gpm. It is built energy efficient though, but still that is a large jump.
You might need to dig in to the insulation thing a little more, or make sure the furnace is actually running as it should. Make sure who ever worked on it last did a combustion analysis and it is right.
Rick

leo95se

rick in Alaska said:

If you are burning 9.5 gallons per day, you either have a huge house or no insulation. On a bad month with my 2400 square foot house in Alaska, I might burn as much as 2 gpm. It is built energy efficient though, but still that is a large jump. You might need to dig in to the insulation thing a little more, or make sure the furnace is actually running as it should. Make sure who ever worked on it last did a combustion analysis and it is right. Rick

Gpm is typically gallons per minute. I’m assuming you mean month? 2 gallons in a month? That’s phenomenal! Of the research I’ve done I seem to be burning at an average (approx 3500sqft).  Trust me I’d love to improve.  I’ll have to seek out a complete analysis to have a baseline. I can’t imagine all that much is going to the hwh so chalk it up to a less than ideal furnace burn.  

Thx!

leo95se

hot_rod said:

Are you on a well, or city water?  Well water stays fairly consistent around 50 F. Public water, when stored above ground can get much colder, down into the 30’s in cold areas. So performance of any water heater depends a lot on incoming temperature
Performance ratings are usually based on 70 or 77 degree temperature rise

 crunch the numbers, I suspect the HPWH will be the least expensive to run and maintain. Even without rebates 

Your equipment is not all that old, might just run with it

Yea in the short term I think you’re right.  Everything is too new to toss it. And I did just buy a house. Ha. Let me toy with the hphwh a bit more. Elec isn’t cheap in the NE (assume .22/kWh) so let me try to compare.  Thanks for the sanity check.  

DJD775

@leo95se For reference I live in RI and heat a 2500 sq.ft. house with an 2x oversized oil boiler and use ~ 5 gallons per day on average in the winter for heat and hot water.
Having modern equipment you might want to explore upgrading insulation and air seal to reduce your heat load. Many utility companies offer a free energy assessment or you could pay for a more thorough assessment.

hot_rod

Once you have the actual delivered cost of the various energies, use this calculator. It allows you to change efficiency. Consider a fossil fueled standard water heater around 75- 78% efficient. In the best case the hpwh could be 30o% or more depending on ambient

https://coalpail.com/fuel-comparison-calculator-home-heating

rick in Alaska

leo95se said:

rick in Alaska said:

If you are burning 9.5 gallons per day, you either have a huge house or no insulation. On a bad month with my 2400 square foot house in Alaska, I might burn as much as 2 gpm. It is built energy efficient though, but still that is a large jump.
You might need to dig in to the insulation thing a little more, or make sure the furnace is actually running as it should. Make sure who ever worked on it last did a combustion analysis and it is right.
Rick

Gpm is typically gallons per minute. I’m assuming you mean month? 2 gallons in a month? That’s phenomenal! Of the research I’ve done I seem to be burning at an average (approx 3500sqft).  Trust me I’d love to improve.  I’ll have to seek out a complete analysis to have a baseline. I can’t imagine all that much is going to the hwh so chalk it up to a less than ideal furnace burn.  

Thx!

I actually meant 2 gallons per day. Per month would be nice though. And, that does include hot water. Insulation and air sealing really pays off in the long run.
Rick

leo95se

DJD775 said:

@leo95se For reference I live in RI and heat a 2500 sq.ft. house with an 2x oversized oil boiler and use ~ 5 gallons per day on average in the winter for heat and hot water. Having modern equipment you might want to explore upgrading insulation and air seal to reduce your heat load. Many utility companies offer a free energy assessment or you could pay for a more thorough assessment.

It’s scheduled for the 26th of this month.  I had a company come out that wanted to charge me to reinsulate everything (at a crazy price).  Finally found a place that could commit to an assessment.  Things have been painfully slow here. 

JakeCK

leo95se said:

Hi all 
excellent info, thanks!
I live in CT, and have a direct fired forced air furnace which is my AC source in the summer as well.  So it seems the indirect hwh thing wouldn’t work in this case?

  

No it wouldn't work in your case. For some reason I was thinking you had a boiler. My apologies.

JakeCK

Also hot rods point about your equipment being new is correct. Pitching new equipment to save a few bucks might not make sense. It's really a case of having to run the numbers. For me it made a lot of sense. My old tank was 14 years old, I was capable of installing it my self, it allowed me to abandon an entire chimney, and I have a solar system that  has a 110% offset.

It bumped up my monthly usage by 100 or so kWh a month, at least in the winter. With a family of four. It'll be interesting to see what happens in the summer since the reservoir that holds my water is above ground and is currently hanging in the upper 30's. It hurts my teeth this time of year when I brush and I do not have sensitive teeth...