How to Choose the Most Efficient Boiler | This Old House

The heating bill for the Arlington house reached the thousands. Richard Trethewey and Kevin Bilo are installing a new heating system that will take a huge bite out of that bill. At the heart of the new system is a state of art boiler that goes in today

The Arlington house will soon be more efficient now that there’s a new boiler getting hooked up. Richard Trethewey shows how old condensing boilers get clogged with sludge in the heat exchanger and burner parts of the system. Newer heating units address the sludge issue with a better design so there’s no place for it to collect. The flue gas gets vented out a plastic pipe through the inside of the house and then up through the roof at the back of the house. Richard and plumber Kevin Bilo connect the flue pipe to the new boiler. There is still much to be done to install the new boiler. Supply and return lines will be run to mixing valves, pumps, and manifolds to connect to radiators and radiant floor heat. Additional piping will feed the hot water tank. This efficient system will work well for a remodeled home.

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This Old House is America’s first and most trusted home improvement show. Each season, we renovate two different historic homes—one step at a time—featuring quality craftsmanship and the latest in modern technology. We demystify home improvement and provide ideas and information so, whether you are doing it yourself or hiring out contractors, you’ll know the right way to do things or the questions to ask. Our experts including general contractor Tom Silva, plumbing and heating expert Richard Trethewey, landscape contractor Jenn Nawada, master carpenter Norm Abram, and host Kevin O’Connor give you the tools you need to protect and preserve your greatest investment—your home.

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How to Choose the Most Efficient Boiler | This Old House

[rafaelarias]

Richards favorite line: "I've got a cutaway here..."

[NathansHVAC]

That boiler is the Vitocrossal 300 CU3A with the 79 gal Vitocell 300-V domestic hot water storage tank. The vent piping is PolyPro from DuraVent. The advantage of this type of high mass boiler is that it doesn't require a high flow secondary loop. The existing pumps and loop from a cast iron boiler will work fine.

[erichardy]

My buddy went to this job and had to rip everything out due to the insane control system and they used some sort of new plastic piping they probably got a deal on and they went out of business so we had to rip everything out. Good job guys

[billiamc]

We hooked up a super efficient Triangle Tube boiler that hangs on the wall...been working excellent for 11 years without a single issue...we also use soft water and paid a fraction of the unit they are installing here.

[myid]

Looking forward to the MRI episode where Richard shows us a cutaway of a Richard and tells us all how he works

[vincenzotesoro]

It’s great to get an understanding of these boilers when purchasing a house with a gas fired boiler thanks very much really appreciate it

[robertyoung]

There is so much to break down.
Very interesting.

[flyingmachineworks]

96% is great and about the top. But when it comes down to it cost per btu. Oil fired units are hitting low 90’s now and have more btu per gallon than propane. So once you factor that and the extra maintenance and that comes with a modcon boiler, are they cheaper over the life compared to a good cast iron boiler?

[dtbroad]

I wish they would tell you the cost of the install and equipment. It has to be upwards of fifteen grand plus.

[victoryfirst]

Does the three feet above the chimney flue vent pipe take into account the peak A part of the roof ??? Thanks

[Keegeth]

That’s a viessmann boiler. They make very good boilers. Not sure what the model is though.

[tomb]

Hi Richard, I'm Huntington NY, on Long Island. I need a new HVAC system. I have oil (Dirty) and want to convert to gas, also I have no duct work. Oil tank is almost empty. What do you recommend, when can you come? Thank you for all the great shows over the YEARS!!!

[paulsmith]

I’m amazed the fan on the boiler will push the poc’s that far with so many bends on the flue, in the uk manufacturers state maximum lengths in meters, deducting for elbows and 45 bends, also that flue looks like standard drainage pipe?

[MrRatanshah]

Connecting the boiler to a storage tank and then distribute to multiple manifolds may be even better as there is only one source calling for " HOT " water. Stored Hot water can supply heat to domestic supply and also radiant ( higher mass system creation ). Not sure of the brand of the Boiler shown.

[jochimbenschneider]

What is the best boiler for a newer home like mine? I have a Seer 18 Electric heat pump and air handler. Seems like it costs several hundred yearly to keep this heat pump running right and they only last 10-15 years.

[tomb]

Hi Richard, What is the manufacture of this system? I need a new hydronic system, I currently have oil baseboard heat and want to switch to gas. I would love to hear from you and your thoughts.

[tomb]

What Type and Manufacture burner is this?

[kylepost]

This heating system is worth more than me.

[BM-plvv]

Looking for new & simple direct vent (no chimney) gas boiler (80% efficiency is fine) that has best shot to last 20 to 25 years and is low maintenance - zero bells and whistles. My focus is not efficiency. Priority = low maintenance and longevity. Currently running 1991 Slant Fin V90 - 80% Direct Vent - baseboard forced hot water - has been excellent, but time to change out. Thoughts, guys/gals? TY!

[moutrap]

Its probably all fine and code compliant since they are doing it but I don't feel so good about these snapping pipes with no glue