What is your opinion on High Efficiency Combi heating units?

[Amir P.]

I am curious what everyone's experience is with the High Efficiency Combi (heat and hot water) wall-mounted heating units. I am currently going through the process of converting from oil to gas on a 3 family rental building and trying to figure out what is the best approach. 

I have one 2021 boiler, one 2006 boiler, and one very old boiler that needs to be replaced. All 3 water heaters are electric and toward the end of their usable life. 

scenario 1: Total $19,400

1 new gas boiler, $6K

2 gas burners to use on existing boilers, $6K

3 new water heaters, $3,600

chimney liner, repair, waterproofing etc, $3,800

 scenario 2: Total $17,625

3 new high efficiency wall mounted combi units $16,500

chimney work $1,125

I'd appreciate any insight regarding this process, the high efficiency units, maintenance, reliability, availability of parts, ease of use and repair or if there are any other alternatives I should be considering. 

[Karl Denton]

YES! I’m so happy you asked this! So I just went through something very similar with my 3 family. So BIGGEST thing is the quality of water in your area. Manchesters water is absolutely terrible for these units and if they aren’t flush on a regular basis you will have blocks and all sorts of issues that will lead to higher expenses down the road. What I did was Bosch Greenstar heaters ONLY and not the water heater combi units. I also talked to others in the area and those that went with combi units are regretting it. I went with natural gas from the oil and this way the tenants pay there’s own heating bills, also more efficient and less yearly maintenance. As for hot water I’d honestly look at a hybrid hot water heater, they are very efficient and cost like under 250$ annually in electric. You can then include hot water in rent and get an increased rent. Message me for any other questions!