Trying to decide on a system...

brandonf

Hey folks, we are remodeling a 1-story bungalow and we plan on installing warm board.

The entire space is less than 1400 sqft.

It's three bedrooms with open concept living room, dining room, front foyer, and kitchen,

Two baths, and a small pantry off of the kitchen,

We are going to have each bedroom and each bathroom on their own zones.

We are really trying to decide if we should go with the warm board modcon boiler or use a traditional boiler.

We are trying to figure out what will be better in the long run based on longevity, emergency repairs, and efficiency.

I have concerns with modcon boilers that have too many electronics that can fail at any time and leave us without heat. And that could be especially bad if the part is backordered.

I also hear that mod con boilers do not last as long as traditional boilers…so I'm really trying to figure out what will be the cheapest option in the long run in a 20-30 year span....

We will be using LP for fuel.

Thanks in advance for your suggestions.

Also the house is in Rhode Island and we are open to recommendations for great installers.

(Not too many listed on heatinghelp's contractor list for the area.)

Thanks

EdTheHeaterMan

LP gas where I worked in southern NJ cost more per BTU than fuel oil or natural gas.  That said if you are starting from scratch, you have no reference point to compare the oil fired conventional boiler with the conventional gas fired boiler.  I had a customer that went from an old oil fired boiler to a System 2000 oil boiler and saved big time, while the neighbor across the street took out their old conventional oil boiler and installed the lower cost conventional gas boiler.  Their LP Gas bill was significantly higher than the oil bill from the old boiler that was removed.   

I give you this story to let you know that the price of LP gas and a conventional boiler that will last up to 30 years or more, might be a little too expensive to operate.   That would point me to the Mod-con boiler in your case because the operating savings will even out over the 15 to 17 year life of the boiler 

You may even want to look into the System 2000 gas boiler options in order to use their energy saving control system along with their energy efficient boiler designs.  But you will want to use them only if there is a EK dealer near you for installation and annual maintenance. If service is too far away then stick with what your installing contractor is comfortable with servicing in the future. That boiler will be there for a while and you need someone to do the maintenance.

Mad Dog_2

Depends how handy your are with modern electronics & motherboard stuff....Many folks 45 & under are very good with basic computer programming & noodling around and can quickly learn their high tech equipment.

If that is the case, and you feel froggy, jump on the Mod Con, they are excellent. If you're not, & you don't have a local company that can work on it, stay with traditional atmospheric equipment. Mad Dog

Cyclist77

We have radiant floor heat in our home and for 15 years have used a coal stoker boiler. Making the switch to NG and spent the winter wrestling with the same question that you have! In the end we went with a Weil-McClain CGa NG cast iron boiler. Yesterday are not as efficient but I am look for simplicity and long life.

GroundUp

I believe the "WarmBoard boiler" is just a Lochinvar Noble with a different sticker and a gross upcharge. Personally I'd stay away from WarmBoard branded anything, but the Lochinvar Noble is a great unit and well supported in most of the country. Longevity might not be what a cast iron unit would, but assuming proper piping and setup of the system, you're probably looking at saving upward of 100 gallons of LP per year with a mod/con over a conventional so I think the proverbial juice would be worth the squeeze. Regarding a contractor, somebody local with a good reputation of knowledge with their boiler of choice is much more important than the brand/style itself. Those guys aren't always easy to find, as most are likely to tell you that they know everything and their stuff is the best, but the reality is that those same guys often do poor work with minimal knowledge. Best of luck

hot_rod

I'd start with a heat load calc. It's very possible a 1400 sq ft well built home could have a load under 15,000 BTU/hr. I doubt many choices in conventional boilers in that size.

Next look at SWT. With WB at those hypothetical load numbers You will be well under 120F, maybe more like 80- 90 degree SWT, depending on floor coverings. That is a shout out for a condensing boiler.

Running a conventional boiler at those temperatures is a lot like driving with the accelerator floored and using the brakes to adjust speed. Doesn't make a lot of sense.

Don't count on warm floors if the loads are 12 btu/ sq ft or less. 10 btu/ sq ft would be a 75° floor surface .

What about AC?

Personally I'd look at panel rads if you really want a hydronic system. Maybe warm floors in the bathroom(s))

Probably others will steer you towards mini split, especially id AC is a requirement.

Complicated, I know!

RascalOrnery

For curiosity, what's the smallest output mod con boiler roughly, and do they make boilers that modulate firing rate but are not used for condensing or if they go together?

Are there "on demand" boilers much like domestic hot water units that use gas?

hot_rod

https://forum.heatinghelp.com/discussion/comment/1854411#Comment_1854411

Lochinvar has a 55,000 that modulates to 8,300 bTU/hr. I don’t know of any that are much smaller

All boilers are on demand, send a thermostat signal and they fire up

I don’t know of any cast or copper that modulate that low

I would not recommend an instantaneous water heater if that is what you are asking?

LRCCBJ

For such a small building, I would install a conventional HW heater. Period.

You need HW in any case and to do that properly with a boiler, you'll need an indirect to go with it. A costly installation that takes up quite a bit of space.

Consider the conventional HW heater.

1. Low installation cost
2. Extreme durability
3. 20 year longevity if anode rod(s) are replaced periodically

A few caveats:

1. You'll need to use a FPHX for the CH. You don't want to mix the CH with the domestic hot water. The cost is not excessive.
2. You'll need to calculate the radiation carefully for 140F SWT. You cannot get more at the point of delivery without using a commercial water heater.
3. The combustion efficiency of the HW heater is not great. About 65%. However, it gives quite a bit back in the insulation. The heatloss from the HW heater is a fraction of the losses from a conventional boiler and is still better than a mod-con.

My opinion is that the HW heater operating and installation costs will be less than the mod-con over 20 years and the durability compared to the mod-con is priceless!

Alan (California Radiant) Forbes

https://forum.heatinghelp.com/discussion/comment/1854520#Comment_1854520

@LRCCBJ makes a good point. I have one or two customers that have a 35 gallon Polaris condensing water heater for their DHW and a heat exchanger pulling off it for their radiant. Seems like a perfect fit for a small house.
The Polaris water heaters come 35 and 50 gallon I believe with quite a few BTU input choices.

hot_rod

Polaris were a great radiant option, back when they were $1500.00. I think by the time you add a FPHX to one it will be a lot more than a mod con combi.

I think the BW/ Laars CombiCors have gotten crazy expensive also. That was a nice option for small jobs.

Basic gas or electric WH are often a good option. If the non ASME doesn't scare you??

Alan (California Radiant) Forbes

Figure a 20-25 year lifespan. PPI (Price Per Ignition) is among the lowest. On the older models, the differential was a low number you couldn't change and they would short cycle like crazy. The newer models are adjustable.

Run them at 140℉ with a tempering valve and you won't go through igniters as much. Condensing efficiencies. No ODR, though. No worries about low return water temperatures. No "B" vent. Relatively quiet. Small footprint. They're a bitc* to work on - flat on your stomach. What's not to like?

LRCCBJ

I was thinking of a smaller and less costly unit:

https://www.supplyhouse.com/AO-Smith-GPVT-50-LP-50-Gallon-50000-BTU-ProLine-XE-Power-Vent-Residential-Gas-Water-Heater-LP?

50G

50K input

70% UEF

Side ports

Take a long time in efficiency savings to pay for the Polaris.

As mentioned, you wouldn't want to work on one.

Alan (California Radiant) Forbes

https://forum.heatinghelp.com/discussion/comment/1854564#Comment_1854564

So, a 50 gallon water heater for DHW with a HX for radiant in the middle of a Rhode Island winter? Could work if you disable the heating half an hour before you shower.

HVACNUT

How far away from civilization is the bungalow? Can a service vehicle get there in a hour... in February... during a snow storm… uphill… both ways? If I wanted no fuss, no muss, it would be a standing pilot cold start with a buffer tank.

LRCCBJ

https://forum.heatinghelp.com/discussion/comment/1854593#Comment_1854593

If the heatloss is 28K on the design day, the WH might be a bit marginal. If you wanted certainty on the design day, just use the GPVX-75L. Personally, I think it is overkill for one or two days per year.

I've run the 75 in a 1900 sq ft building with issues only below 10F. It feeds all CI.

Kaos

A power vented water tank with a UEF of around 70% runs about 80% efficiency for space heat. The reason for the higher efficiency is you don't have the large standby flue losses. Energystar used to list space heat efficiency separately for the combi rated units, not sure why it is not there anymore.

A power vented unit with a big burner will easily work. This is a common space heat solution for low load places such as townhouses around me with a tank feeding a hydro air coil.

I know people here frown on it but if your water is not hard a tankless unit can also work. This can get you 90+ efficiency with a bit of design. They do require a pretty expensive high head pump though.

Alan (California Radiant) Forbes

Warm Floors was a company in Napa who were pioneers in radiant heating around here. They had the plumber provide the heat source; usually a 75 or 100 gallon water heater to feed their HX for the radiant. Worked beautifully in the winters, but was was inefficient in the summer when all that water was kept hot and not used.
They changed their name to Warm Corp. West. Warm Floors was a great name, but my guess is that they did their work too well; some floors weren’t warm even though they heated the house and a homeowner took them to task.

hot_rod

You may still find high output 50 gallon tanks. Used to be 65 and 75,000 BTU/hr. 50 gallons available.

I think the 50 gallon CombiCors were 75,000 BTU/hr.

Side wall or power vented water heaters have a bit less standby loss.

BKfromEK

Thank you for your post, @brandonf , and kind words about System 2000, @EdTheHeaterMan .

We would recommend zoning comfort areas for the best comfort and efficiency.  This would generally mean zoning the bedrooms together (master and bath separate if applicable).  Multiple small zones typically means more calls, and more heating cycles, which can waste energy.  Our thermal purge design greatly helps with this because the boiler finished cold instead of hot like all other boilers.

You may want to consider chimney vented systems for simplicity, especially if you have baseboard heat, which typically is designed for 180°F supply water.  Another point, you may want to consider oilheat (138,600 BTU/gal) as the price per unit of energy is often much less than propane (92,000 BTU/gal).

If you’d like to find out more about our high efficiency chimney vented and side wall vented heat and hot boilers, thermal purge, longevity, industry standard parts, or more, please feel free to PM or call me, visit www.energykinetics.com , or contact Energy Kinetics customer service at (908) 735-2066. If you let me know your location, I can connect you with your territory manager who can also help answer questions and provide qualified contractors in your area.

Brian Kiernan

National Sales Manager

Energy Kinetics

908-735-2066 ext 201

TAG

I was a very early user of Warmboard (about 20 years ago). One story addition on a slab. The Warmboard S went above the slab/ ridged foam insulation w/ wood to match the rest of the house. Have used it in some way on every project since. It's not cheap … but it works and no more solid floor exists when you use the Warmboard S.

Obviously you need to have a very good heat/ cooling load done on the building so you understand what can and can not be done. Especially if using spray foam. Doing Radiant is not to save money … it's comfort. The comfort level with radiant grows when buildings have more glass and odd spaces .. very tall ceilings.

Warmboard will do the layout for you and the need/ ability to zone depends on the project. Often you can zone and then decide later if it's really important … most often it's not needed room to room. In larger projects it makes more sense and the nice thing about Warmboard is the speed the panels will heat.

The low temp water that is required is going to direct you to a mod con or one of the specialized two coil water heaters …. all depends on the heat load.

I have not used the new Warmboard boiler and controls .. it's a slick system and they needed to offer a full system because there is not a lot of knowledge out there. Warmboard is not going to be used in a budget project — builders what a system that will work. Cost is often secondary. Finding someone willing and able to design and install a boiler room is often the biggest problem. Warmboard needed to offer an out of the box solution that most professionals can install,

My last project only used two zones but we did layout the Warmboard with the possibilities of having more. We used two manifolds with everything open and two zone vales. Larger manifolds are cheap today so the extra loops for the zones did not add much to the cost and provided a fix if we were wrong about only needing two zones. We ran control wires as well and buried them.

One of my previous projects was very complex and we wanted full control and I used the cross manifolds vs all the individual zone controls.

brandonf

Thank you for all the responses everyone.

Based on the temperatures we are looking for, and the fact we don't have a chimney, we will probably be going with a ModCon.

I need to find someone who can do a proper heat loss calculation for the building.

Since warm board recommends Lochinvar, I should probably contact them and ask them for a list of certified installers in my area.

Our hot water tank will be a traditional standing pilot LP tank simply because we won't need power for it to work in case of an outage in the winter.

Lots to consider 🤷🏽

weakoak1124

@brandonf I PM'd you a possible contractor.

Alan (California Radiant) Forbes

You can also ask your local hydronics supplier(s) for references. I'm sure they would give you some names of contractors that buy from them. And then check references on those contractors.