Consolidate 2 boilers?

handrailer

I have an older 2 story home. A duplex w the entire 1400 sq ft 2nd floor being a rental apartment. There are 2 (35 and 40 yr old) boilers w tankless coils each servicing the hot water baseboard and providing hot water for each apartment 

      I'm mostly heating my own apartment w a wood stove to minimize the use of the one furnace, but obviously and overall this has got to be inefficient. I have found it difficult to retain tenants when they pay for their own heat and therefore now include heat w the rental

      With the current cost of oil, I am dreading the approach of winter. Last year, even w burning 4-1/2 cord of wood, I used 1375 gallons over 12 months. 
      The furnaces are about 6 ft apart. I've been told that either of them have the capacity to heat the whole building. 

    I'd love to have some idea of what could be saved if the two baseboard systems were consolidated around one furnace. Are boiler/furnaces of this age and type worth messing around with?  Can the tankless coil water heating be deactivated and the hot water then drawn from a propane water heater?

Robert_25

My $0.02 is that those boilers are at the end of their life. Although they may continue running a long time, I don't think it is worth re-piping the entire heating system to utilize one of those old boilers. A properly sized triple-pass boiler with an indirect water heater would definitely use less oil, but I am not sure how much less. Ideally you would tighten the house up first, so the new boiler can be sized against the reduced heat load.

"Can the tankless coil water heating be deactivated and the hot water then drawn from a propane water heater?"

Yes, but that may or may not save you money depending on your propane pricing. You would also have to modify or replace the aquastat on the oil boilers to allow them to go "cold" when there is no heat demand.

pedmec

I would never combine two separate heating sources into one and include it in the rent. Once you do that people have no regards for who's paying it. They will just jack up the thermostat whenever they want. Leave the house with it on 80 and don't care. Take extremely long showers. Wash everybody's close in the neighborhood. Why would they care. Their not paying for it.

I use to install replacement heating systems just to split them up. I had a customer who was buying property (multi dwelling) back in the 2000's and we would split up the heating systems so the tenants have to pay their own bill. Bunch of three families with one boiler. Put three individual boilers in. Watch the thermostats go from 80 to 70 once they get that first heating bill.

STEVEusaPA

With the cost of rent shooting up, available rentals becoming scarce with high demand, I’d make the tenants pay for their oil.
I agree both of those boilers look pretty rough.
If they pay their own electric you could move the domestic hot water to electric.

EdTheHeaterMan

I understand that keeping tenants can be difficult once they have to pay their own oil bill. I am guessing that there is no natural gas on site. Since it is time to get new boilers, I would consider LP gas for a separate water heater that can easily be split to 2 separate water heaters in the future if desired.

The space heater can also be combined to only one very efficient EK System 2000 oil or gas boiler or any other super efficient brand boiler. You can separate the zones by zone valves for now. That way, your wood stove won't affect the second floor apartment.

If you ever decide to go with separate boilers in the future, you can just add another very efficient boiler. If there is a chance to install Natural gas in the future, then the appliances can be converted as long as you purchase the proper equipment today.

If you are looking to use only one of the existing boilers, I would select the New Yorker Steel boiler, (the Green one, even though it is older). I believe it is a more efficient design. You can modify the existing Boiler Aquastat so it does not make hot water, and disconnect the DHW piping. IMPORTANT: Do not cap off the Hot and Cold water pipes to the coil as there may be a pressure build up that can cause a real Dangerous problem. Only cap them off if they start to leak in the future... that means that the hot water coil is leaking and therefore will have a way to release any overpressure

Will this be DIY or are you considering getting a PRO? There are not too many Professionals that would take on this "OLD BOILER re-design" work.

JDHW

If one boiler is the best heating solution you could zone the system for the two areas and add heat meters. That would allow you to split the fuel costs based on actual usage.

John

Robert_25

pedmec said:

I would never combine two separate heating sources into one and include it in the rent. Once you do that people have no regards for who's paying it. They will just jack up the thermostat whenever they want. Leave the house with it on 80 and don't care. Take extremely long showers. Wash everybody's close in the neighborhood. Why would they care. Their not paying for it.

It a balance of one set of problems for another. I have had a similar discussion with friends that own rentals, and making the tenants buy their own oil comes with its own challenges.

1. They run out of oil.
2. They turn the heat way down when leaving for a few days and pipes freeze.
3. They move out with an empty tank and leave the landlord to deal with the no heat situation.

STEVEusaPA said:

If they pay their own electric you could move the domestic hot water to electric.

Good idea. Keeping those two boilers hot all summer probably uses 2 gallons of oil per day. At least if the tenants are paying for the electric the landlord doesn't have to pay for the marathon showers mentioned above.

Thermostats limited to 72F are something else to consider.

pedmec

1. They run out of oil.

That's on them, not you. They ran out, they can pay for the bleed.

2. They turn the heat way down when leaving for a few days and pipes freeze.

You get thermostats that maintain a minimum temperature or you add freeze protection measures. Whether its controls or glycol.

3. They move out with an empty tank and leave the landlord to deal with the no heat situation.

Put minimum amount of oil in until you get new tenant. You can charge the new tenant for whats in the tank.

EdTheHeaterMan

There is no response from @handrailer here or on private message. So lets help someone that actually reads our answers.