Make my house efficient: Energy Kinetics Resolute vs VitoRonds vs PurePro Trio vs Mitsubishi?

bobzel

I just moved into a house that has 25+ year old oil boiler that is loud and inefficient. I'm looking to upgrade to something as efficient as possible since I intend to be here for a while. I've been told the EK resolute is the most efficient, although Viessmann systems have a great reputation around here. The PurePro is something that another home owner has.

I currently have an indirect water tank, but I like the idea of going tankless assuming that's not going to add significantly to heat bills.

I'm also thinking about installing a Mitsubishi heat pump which would hopefully reduce my need for oil except for the coldest of days.

So, does an EK make sense if used less frequently except for hot water? Do the other boilers offer any advantages over an EK (are they likely cheaper?). Are there any good resources for evaluating all the available options (including converting to propane) - each contractor I contact seems to have a very limited view of things.

EBEBRATT-Ed

I would not convert to propane as propane is always more costly than oil or natural gas.

Mitsubishi is considered the top of the line for ductless heat pumps although Fujitsu is good as well. Stay away from the systems that use multiple heads with one condenser. A heat pump is useful for back up and in the spring and fall it may not be comfortable for heating in the dead of winter.

As far as new boilers go the contractor and the quality of the installation are far more important that the boiler you choose. The best most efficient equipment installed by a slob will not make you happy at all. And the quality of contractors in some areas is......troubling.

You migh want to check "find a contractor" on this site and post your location. Ask friends and neighbors for recommendations.

I would avoid the tankless hot water systems...nothing but trouble.

As far as boilers go IF you have a good EK dealer in your area that would be my first choice but Pure Pro Trio and Viessmann are good equipment as well

Jamie Hall

Well... Step 1 is going to be a heat loss calculation (often called "Manual J) for the house (I presume this is a hot water heating system?). You can't do anything without that.

Having done that, you will be able to determine what size boiler you need.

All the makes you mention are very good to excellent. Price is, of course, a consideration. A more important consideration is the contractor doing the installation. Even the best boiler made will not be good with a poor installation, and often a contractor will have a make of boiler he or she prefers to work with -- and to maintain.

Tankless water heaters have their points. You would pretty well have to go to propane for that, unless you have and are allowed to install natural gas. Sticking with the water heater, though -- they are good if your usage is within the capacity of the unit. Many of them really shouldn't be used for more than one bath, or maybe a bath and a half bath, plus other household needs such as the kitchen.

I am not fond of "combi" boilers, though sometimes they work out well. Indirects, however, are very good, unless you are in a southern climate where the boiler isn't used much for heat.

Would the heat pump you are considering by air to water? If you are thinking air to air you will either have to add a good deal of ductwork or use "minisplits"

On converting to propane: propane is going to cost more. Possibly a lot more. Than the oil does.

Hot_water_fan

I currently have an indirect water tank, but I like the idea of going tankless assuming that's not going to add significantly to heat bills.

Tankless has very few benefits besides space savings. If that's important, it'll work with propane, but otherwise it's not valuable, just shiny.

Energy Costs for oil vs. propane vs. electricity should be converted to $/MMBtu Output for comparison:

Oil: $/gallon x (1,000,000/138,000) / COP %
Propane: $/gallon x (1,000,000/91,500) / COP %
Electricty: $/kwh x (1,000,000/3,412) / COP %

Using EIA national averages, here are the costs. They will be different for you, but now you have the formulas.




@Jamie Hall is right as per usual, air-to-water would be a good fit. Otherwise, ductwork would help distribute the heat from the heat pump, with the added bonus of AC if that's desirable where you are.

If the heat pump can cover most of the winter, I'd consider repairing the existing boiler and just keeping it as backup.

bobzel

I like the idea of an air to water heat pump but I don't know anyone who has one nor do I know any contractors who have experience with them. I tried the Find a Contractor link here but it didn't identify anyone near me (swansea ma)

I contacted energy kinetics who sent me 3 installers who I don't know so not quite sure how to evaluate their work other than asking for references.

I also like the idea of heat pump ac but I haven't been here long enough to know how much I need that.

hot_rod

You need to look at fuel cost in your area to make an accurate comparison. Midwest and rural areas LP is often the most cost effective, and can get you into 90% plus efficiencies. The EIA site has regional breakdown costs and history.

The key with LP is to own your own tanks and lock in or pre buy in late summer

Roger

Thank you for your posts @bobzel , and for everyone's comments.
Regarding contractors, Energy Kinetics has close contact with all of the contractors we recommend, so we know them and we have seen the good quality work they do (several are listed on HeatingHelp). We've been in business for over 40 years and have a strong track record with our territory managers and dealers to make sure our equipment is installed and serviced properly. If there is an issue, we will coordinate to help make it right.

This may be alot to post, but I think worthwhile to review:
Regarding efficiency, AFUE does not apply to heat and hot water boilers. We have a webpage that reviews field performance largely based on a Department of Energy Lab study. Energy Kinetics low mass with thermal purge (System 2000) tops the list for best efficiency, with non-condensing oil edging out modulating condensing gas.
Minisplit heat pumps also have ratings concerns with field performance that is typically 20% to 30% below current manufacturers ratings as seen in this recent testimony to the Massachusetts Public Utility Commission. As is also well documented, heat pump efficiency drops as temperatures get colder, and this effect and the field performance are detailed in this document and on the chart on p.5. At $0.23/kWh for Massachusetts ($9.34/gallon oil equivalent) and using rough math at 40° F and a COP of 2.8 comes out to $3.33/gallon oil equivalent.
The testimony also details studies that demonstrate that "low heat pump utilization by customers in winter weather is a near universal phenomenon"; this looks like the cutoff is around 35°F from the chart on p.7. If you need air conditioning, that may move you in the direction of a heat pump for mild heating weather.
Best,
Roger

Hot_water_fan

Thanks @Roger !

That Brookhaven study can almost drive now, would love if they put out an updated study to see how many imitators EK has now. Thermal purge might be the sincerest form of flattery .

Roger

Thank you for your comment, @Hot_water_fan .
Thermal purge needs to work for both heat and hot water to prevent energy waste, so the boiler has to be low mass and low water volume. Tanks with coils finish the thermostat call with the boiler, tank and coil hot so the boiler cannot effectively purge much left over energy. A tank with a plate heat exchanger can heat from the top of the tank down so there is a reservoir of cold water at the bottom of the tank that balances with the heat left in the boiler; the tank can then finish hot and the boiler cold saving energy each hot water cycle.
A rare few may claim thermal purge controls, but it all has to be done right to save energy.
Roger

Hot_water_fan

@Roger makes sense to me! I remember the study's modcon test regiment wasn't great either - they locked it at like 100% and 50% output if I recall correctly. Seeing an updated version with full modulation and an ODR simulation would be awesome.

Roger

I just reviewed the report for the modcon. It was tested with supply temperatures from 121°F to 172°F (possibly similar to ODR), and return temperatures from 106°F to 137°F (much lower than typical hydronic systems). It was tested at low, medium and high input rates, and although it could modulate, the load on the boiler and the firing rate were fixed at each test point to determine an accurate efficiency including condensate collection.

hot_rod

Your first sentence in post sums it up. 

Make my house efficient

Best money you can spend is lowering the load, tighten up the structure first. Then a load calc and product selection.

Roger

Great comment, @hot_rod .
I'll add that there are sometimes site specific "low hanging fruit" upgrades that provide cost effective air sealing/building shell improvements. At other times, it makes sense at the time of replacement (windows, doors, R-5 insulated wall sheathing at siding replacement for example).
On the equipment side, installing something that won't be effected when future energy retrofits will lower the load is the best strategy. This is where low idle loss is so important, as low idle loss heat and hot water systems have virtually no oversizing penalty. From the study referenced above, our (low idle loss) low mass boiler with thermal purge operates at near steady state efficiency with extremely small loads. So whether it's spring or fall, hot water only in the summer, or a significant load reduction due to a strong weatherization retrofit, the boiler will still deliver near peak efficiency. At the other end of the scale is typical central air conditioning that can have real problems with comfort and dehumidification if it becomes grossly oversized due to a significant reduction in load from building shell improvements (or due to improper sizing from a missing load calc).
Roger

Robert O'Brien

The ROI on a new system that can deliver 30% savings is far beyond that achieved with air sealing and insulation. The low hanging fruit that Roger mentioned is the exception, assuming you do it yourself.

BDR529

This day and age. No proprietary controls. Decent Cast iron boiler, Honeywell controls or as close as you can get.

pecmsg

Tightning the envelop will give you the highest return on investment.

Going from your 85% oil boiler to a high efficiency gas boiler may save you 10% of fuel usage. Doubt youll see the savings for many many years. Add the additional repair costs for this savings at best it's a wash.

Get a blower door test done, tighten the envelope and you can seriously reduce the BTU/h required, then you'll see savings.

Roger

Thank you for your post, @BDR529 , as it provides a good opportunity to reiterate that Energy Kinetics’ controls can be bypassed for emergency heat by moving just a few wires in only a couple of minutes, or a service board can be installed for emergency heat. Here is a link to more information regarding the controls, support, and the service board.
https://energykinetics.com/system2000-parts-trade-list-price/

There’s no reason to compromise on efficiency when systems are designed for ease of service and resiliency. And even more so when support is also readily available.

 Best,
 Roger 

Roger

Thank you for your post, @pecmsg , and although I agree tightening the envelope can save energy, I respectfully disagree about the potential energy savings with boiler upgrades. Savings are well documented to be much greater than estimated with AFUE alone, especially when upgrading older, poorly insulated systems that maintain temperature to high-performing systems with better insulation and controls (and especially low mass with thermal purge per my links above).

Best,
Roger

pecmsg

@Roger
For Argument's sake only
Say replacing a 150K BTU/h boiler with a similar Energy Kinetics model, how much money will have to be saved over let's say 15 years to justify the total cost of equipment and labor?

My point is I never see a return on investment by Just changing the boiler like for like. Getting a proper manual "J" performed and reducing the size can lead to substantial savings. Enough to cover the entire cost is questionable. A combination of tightening the envelope with reducing the BTU/h output needed then there's a chance to recover the investment.
There is a contractor on the east end of the isl of long that advertised 50% reduction in fuel costs...........I'm sorry but that's not going to happen! 10 or 15% is pushing it.

For the record Energy Kinetics is a very good product.

Motorapido

EBEBRATT-Ed said:

Stay away from the systems that use multiple heads with one condenser.

Why stay away from one compressor with multiple heads? I ask because I have a three-head unit for upstairs air conditioning at my main house, and on my vacation house, I was planning a Mitsubishi in which one compressor would feed two heads. My HVAC guy immediately said, "I'd get a separate outdoor compressor for each of the two heads." But to keep outdoor clutter under control, I'd like to just have a single outdoor unit. What's the matter with the one compressor/multiple heads setup?

Roger

Thank you, @pecmsg - I always appreciate your insightful contributions on HeatingHelp. 

Regarding savings, the Department of Energy lab study demonstrated savings of nearly 40% over old tankless coil boilers and Energy Kinetics newer equipment is even better. A 2021 report from the National Oilheat Research Alliance documented average savings of 25% over older equipment. 

For easy math, if we use 1000 gallons per year and 25% savings at $3.00/gallon, that would be $15,000 savings in 20 years without any escalation in fuel prices; we consider our boilers as having 30+ year lifecycle. 

So in general, I would expect this upgrade to have a good return on investment and even better if the payback is based on the difference in cost vs a lower efficiency alternative at the time of replacement. 

Best,
Roger

Gilmorrie

It has been shown time and again that replacing a boiler that runs won't be economically justified by fuel savings from a more efficient unit. Do your own math - calculate the payback period on the investment. You can likely achieve a shorter payback period by buying a bond. Boiler salesmen will disagree. Your 25-year-old boiler is not particularly old as boilers go.

pecmsg

@Roger

I deal mostly with Refrigeration and A/C, although I do heating not much any more. On the A/C side here in the NE High Efficency does

Roger said:

Thank you, @pecmsg - I always appreciate your insightful contributions on HeatingHelp. 

Regarding savings, the Department of Energy lab study demonstrated savings of nearly 40% over old tankless coil boilers and Energy Kinetics newer equipment is even better. A 2021 report from the National Oilheat Research Alliance documented average savings of 25% over older equipment. 

For easy math, if we use 1000 gallons per year and 25% savings at $3.00/gallon, that would be $15,000 savings in 20 years without any escalation in fuel prices; we consider our boilers as having 30+ year lifecycle. 

So in general, I would expect this upgrade to have a good return on investment and even better if the payback is based on the difference in cost vs a lower efficiency alternative at the time of replacement. 

Best,
Roger

Im not disputing the #'s but do question the data submitted. Using my area Eastern long island would you still see 25 - 40$ savings with a like for like change?

Hot_water_fan

Why stay away from one compressor with multiple heads? I ask because I have a three-head unit for upstairs air conditioning at my main house, and on my vacation house, I was planning a Mitsubishi in which one compressor would feed two heads. My HVAC guy immediately said, "I'd get a separate outdoor compressor for each of the two heads." But to keep outdoor clutter under control, I'd like to just have a single outdoor unit. What's the matter with the one compressor/multiple heads setup?

The one-to-many set up leads to awful efficiency. In fact, Mitsubishi’s engineer said not to do it on a fine home building podcast (yet they still advertise it). 

The issue is that the multi-split outdoor units don’t modulate well and when you put a ductless head in each room (particularly bedrooms) it’s a near certainty that they’re 2x oversized. A multi-split should be a last resort. 

Roger

Thank you, @pecmsg

I would not expect to see savings with a like for like change (same boiler type and AFUE, insulation, mass, controls). Significant savings result from improvements in design related to energy efficiency. For example, just going to thermal purge using a plate heat exchanger on Energy Kinetics' systems will usually save an additional 5% to 10% annual energy  over a tank with coil (not just hot water energy consumption).