What is a Combi Boiler? Compact Mechanicals with Wade Paquin! 

I'm using the same thing in the ICF home I'm building right now.

Yup. Something about mounting these things to a sheet of plywood and venting through plastic makes me uncomfortable. I'd prefer it bolted directly to the block and vented through metal.

What will replace them?

Vs the alternatives it is far from efficient

Code dictates it in a lot of markets. Most of the Northeast is already mandating CPVC/Polypropylene for flue piping, or headed that way.

That's how it's pronounced! TACO is derived from "Thermal Appliance Company"

Condensate pipework must be either plastic or stainless. Anything else metallic will rot in no time. Condensate from boilers is mildly acidic. It’s why the flue is PVC. If you have a condensate leak within the boiler and you don’t realise, you’ll be surprised how much of a mess it will leave. Be careful where you terminate the condensate pipe. It should go into a foul water pipe, not rainwater. During times of the year when there isn’t much rain it won’t get washed away and can lead to damaged drainpipes. If you have no alternative but to terminate in a rainwater pipe, fit an inline neutraliser.

It's a pity that you can't combo a heat pump unit with a water tank easily so that the heat removed by the AC heats the water.

A heat pump can handle any sized property. Just like with gas boilers, you need to install a unit with appropriate power output for the property. The only special requirement for a heat pump over a combi boiler is that the heat pump will have a lower flow temperature at a higher flow rate for the same given BTU/kW. This means a heat pump needs larger radiators. Underfloor heating is ideal. The size or heat load of the building is not something either technology is more or less suited to.

@@jerseygryphon you can, it's called a desuperheater.

@@Aethid read it again. I said "water heater." Of course a heat pump can do anything, but then you also need a water heater (or a system that does both, which is rare).

@@sethborman7844 Heat pumps are *usually* water heaters. The most common kind of heat pump is an air to water heater which can function as a drop in replacement for either a combination or system boiler.

As you should be. I would near install this system myself.

Plenty of this exact type of system in Maine, they work fantastically!

Natural gas or LPG. You get the changeover kit as standard, it’s not a big deal, mainly changing the injectors for ones with a smaller hole (LPG runs at higher pressure), then commissioning the appliance accordingly. You don’t get oil versions. You do get instantaneous electric water heaters, just depends how enormous you want your electricity bill to be. More often than not you’d be as well with a modern stainless high recovery tank using an immersion heater, not cheap to run but very cheap to maintain. Combi boilers on the other hand, very efficient but expensive to maintain in the long run, over its lifespan you’ll replace every single part twice. Worth thinking about if you’re looking at long term cost, especially if you don’t have a huge demand for hot water and can happily live with a smaller tank. Modern cylinders are very well insulated and don’t have much of a heat loss over the day, and are also high recovery, they’ll heat back up quickly.

Sure

I just got a quote for a boiler only unit, 200K btu, 4,000 sq ft house $22K for unit and install on an existing hydronic floor system. I’m sure this is more. This is why they are not common.

The unit is around $2000, do the install yourself and save lots.

Convert old oil boiler to gas based heating and hot water combi without tank. Get quote, New York, 30k. Equipment cost is not main driver here.150 or 200 BTU may be only $1000 diff.

When they're talking about the system Matt mentions that there is a Unico small duct high velocity ac/heater system. That combi boiler provides heat to the Unico.

Which one did you get ?

Propane conversion kit is included in the box

@@bigcrisbie7244 thanks, this system would be a great option for a fixxer upper that only had electric heat (baseboard) and maybe no natural gas. Am looking for the retirement place away from the city and the more options to improve the better !

They have it to him, that's the reason.

Safety sally alert

Until you lose an eye.@@baxt1412

Same in the Netherlands, but in recent year the government started pushing heat pumps more and more. After 2026 no more new installation of gas fired boilers are allowed, unless they're accompanied with some kind of heat pump.

In 2027 they will realize the math didn’t work, and gas tech will continue to be allowed.

In New England, so not exactly TX or the lower Midwest.

Love heat pumps but air to water is real challenge for heating. Not heat pumps fault. Most existing radiators are designed for 180 degree water and that’s really hard to achieve with the heat pumps on the market today… or really like ever.

Hope they provided a bigger electric panel given it’s a good chance in 30 years they will not be able to replace In kind due restrictions on gas usage.

Average combi lifespan is 15 years if a condensing appliance. The heat exchangers deteriorate over time from the acidity of the condensate. Not a prayer of getting 30 years out of it. You can keep them going if the manufacturer still supplies parts but as with anything else, you get to the point where you may as well stop throwing spares around and just get a new one. They do go through parts like they’re off out of fashion. Get on good terms with whoever will be repairing it. That’s not a criticism of this manufacturer, in the UK the majority of homes have combi boilers and they are all as bad in that respect, I’ve been repairing them for 25 years. Like cars, it’s where the manufacturers make their money.

Try a heat pump in -30 f not so good here in New England

@@waltercurtis6930 I have one very much like this. In 30 years I'll probably be dead, so not too worried about it.

Actually a professional knows when and where to gear up for safety. It’s not always appropriate to gear up just to put a screw in. You’d know that if you paid the invoices.

No current worries other than cooking appliances

@@mrstinky2421 You mean being able to buy the appliances? I’m seriously wondering about getting enough gas to meet demand. I really don’t get the nonsense with pipelines through New York. Seems like a 10th amendment violation to me.

🙄

@@drumdude10 Ikr, autism levels of pedantry.

English is not a monolithic language. Lots of languages have features that may seem redundant. In some, the double negative is actually correct, for example.

@@anthonykaiser974 Good luck disproving identity and the law of non-contradiction, but nice red herring..