I need help choosing a boiler replacement for small house that isn't used consistently.

DTclan

I took over a small family house in Cape Cod, MA. 925sq ft house. One floor. One zone. 47' of baseboards. 3 bedroom, 2 bath. 22 year old propane Weil-McLain Gold GV-3 cast iron boiler is shot. Smelled gas. lots of corrosion on cast iron. filled with sediment. HVAC co checked and says it needs to be replaced. Currently have an 18 yr old 80 gal electric water heater which looks rusty and possible rust/leak lines running down it so it looks like it needs replacing too.

Have received very different proposals: solely heat pumps; another cast iron boiler (Weil-McLain GCI-3 or Weil-McLain GV90+3) with an indirect WH or another electric WH; or several different high efficiency stainless steel boilers and WH (mod-con Viessmann, Lochinvar, Ideal, some with 10:1 turndown) . Estimates range up to $35,000 which is almost double my income.

House has a crawlspace with a small area that is considered "the basement" due to its height. Crawlspace was just encapsulated and foundation walls sprayed with foam insulation. Crawlspace vent on far end from the boiler was closed in. An insulated door was added to the bottom of the steps leading into the basement to keep humidity out. Will be running a dehumidifier. Extra Insulation was just blown into the attic. Years ago insulation was blown into exterior walls. Old wooden windows need replacing but they have storm windows and I have storm doors with new seals.

My late husband actually did HVAC at one time but he has passed on and didn't teach me anything about this. So I'm trying to figure this out on my own it's overwhelming. It's confusing because the experts have given me completely different proposals. Not sure what to think. It seems that I may not receive the benefits of the expensive mod-cons suggested so is it worth the extra expense. Was told the same with the condensing Weil-McLain boiler given the small amount of radiators and small heat loss or something like that. We do use two showers as well as laundry and dishes so I think that was considered as not low HW need. We sometimes have 4-5 people staying at the house, sometimes just 1-2.

The house doesn't get used consistently anymore. We do go for weeks or even months throughout the year but not consistent use. Less frequently in winter. Not sure if this what we should have been doing but we normally leave heat set to 58 in winter when no one is there, turning up the thermostat upon arrival. Electric water heater is normally turned off at circuit breaker when leaving for long periods, then back on upon arrival. Same with the well pump.

I'm not sure how our coming and going affects the different heating systems suggested. It's all so confusing and it's getting cold in the northeast. Any advice is hugely appreciated.

delcrossv

Based on cost alone the cast iron WM seems like the best bet. Maybe with a DHW coil instead of a separate water heater.

In any event, you'll need some kind of freeze protection if the house is empty for extended periods in the winter.

DTclan

"In any event, you'll need some kind of freeze protection if the house is empty for extended periods in the winter".

Is keeping the heat set to 58 not good enough? I also have a camera showing the indoor temperature using a large thermometer. I may add a camera in the boiler/WH area in case of leaks or noises. Any other suggestions?

delcrossv

Others may have more, but it seems you're keeping watch.

HVACNUT

The smallest mod con you can find (80K?) and lock it in at 50% firing rate max. Power vent water heater. Plug it in when you get there.

pecmsg

Keep

It

Simple

S

The higher the efficiency the more crap there is to break.

There are t-stats that can monitor and dial out to you and your service provider when the indoor temperature gets below a set point.

jesmed1

As a homeowner, not a heating pro, I agree with the "keep it simple" advice. You're using the house "less frequently" in winter, which means efficiency doesn't matter as much as it would in a primary residence. Not being a primary residence also argues for simplicity, because if you're living an hour away when a complex mod-con boiler fails in your secondary residence, it's going to be a pain to fix.

I would also recommend installing an ecobee smart thermostat. We have two ecobees running two oil boilers in our 4-unit condo building, and the ecobees are terrific. As @pecmsg said, you can program them to email you when the temperature in the house drops below your specified limit. Another reason I chose ecobees over a Nest thermostat is that the Nest does not allow you to program the "swing" or "differential," which is the amount of temperature drop allowed below the setpoint before the thermostat turns the boiler on. If the differential setting is too low, the boiler will cycle on and off frequently, running short cycles which are inefficient. For our cast iron oil boilers, I've found that a differential setting of 1.5 degrees is a good balance between comfort and efficiency. The Nest will not allow you to make that choice for yourself. Last time I checked, the Nest was programmed for 1 degree swing and is not user-changeable.

Another nice feature of the ecobee is an app called beestat. This can be loaded onto your phone, and will show you detailed temperature graphs and performance info for your heating system remotely. So you can check in and see how the heating system is doing remotely. It's a really terrific feature. With 2 ecobee thermostats and 2 remote ecobee sensors paired with the thermostats, I can see at a glance detailed temperature graphs for all 4 units in our building. It will also give you analytics like total boiler run-time per week, per month, etc.

DCContrarian

Have you priced out paying a plumber to drain the pipes when you're not there? I have a house nearby and that's what most of the summer people do. There's just too many things to go wrong trying to heat an unoccupied house through the winter.

Grallert

Keep it really simple. I hate to say it here but I will. I know this will be controversial. My suggestion would be electric. I know the utility is expensive on the cape, I'm from (formally) Martha's Vineyard. But having to service and maintain seasonal systems for folks not actually occupying a house, I've seem the problems. So the cost and maybe worry of monitoring and maintaining any hydronic mechanical system might be greater than a "set it and forget it" modern electric system. If you have the exposure for solar then the recommendation is stronger. Something to look into.

Just a thought.

M

Jamie Hall

I generally agree with the above — keep it simple. Which translates into reliable… Small cast iron plain vanilla boiler. Not sure about the water heater, however. I might be very much inclined, since you have propane, to use an on-demand propane unit for the water heater. Takes up very little space, no standby loss when you aren't there.

Now one other thing. All the ideas noted above for remote monitoring are just dandy, except for one thing. If the power fails for any period of time — even a few hours — so does the remote monitoring. I would advise having some trusted local who will come by when the weather is horrid or the power has been out to check that all is well. Pay them!

And one other thing. Get a good carpenter to repair as needed and adjust the old windows and make sure the storms you have actually work. It will be just as satisfactory as anything short of a top of the line (read many bucks) modern window.

DTclan

Thanks for all the info and ideas.

Kaos

I know these are like swear words around here, but if you are in a place where you need AC, my recommendation would be to ditch the hot water and install standard furnace/AC.

If you don't want to go that route, an option is to install a cold climate wallmount mini split in the living space and another one in the hallway to the bedrooms. You then add resistance baseboard heat to each bed and bath as supplement.

You can then set the baseboards to maintain say 40F and the heat pump for about 50F while away.

I have pretty close to this setup at a winterized cottage and works very well. The heat pump does all the freeze protection heat, the baseboards never run but are there as backup just in case.