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??