Decisions, Decisions...Regarding Oil-Fired Heat

mculik5

Need some help regarding best solution for oil-fired heating for my situation.

Here's my situation:

Live in NJ. Been in this house for a year, and plan to stay here for a LONG time. Heat exchanger on old oil-fired furnace is cracked. Had an independent manual J done, and the heating load is 80K Btu. Current heating system is one zone for the entire house (3200 sqft). It worked well enough last year that I'd stick with one zone if that's the best way to go given my design goals below.

My design goals, in priority order, are:

1. Efficiency - reduce energy consumption as much as possible to save $$$ (especially if/when oil prices go up again)
2. Low total cost of ownership - factoring in initial cost, maintenance costs, fuel costs, etc.
3. Comfort - obviously, but willing to make some sacrifices if necessary to save $$$
4. Longevity - I want a system that will last a LONG time provided I keep up with maintenance (which I will)
5. Low initial cost - I'm a buy once, cry once kind of person; would rather spend more $$$ initially (to a point, of course) to do it right

Here are the options I'm considering:

1. Replace existing furnace with a new oil-fired, right-sized furnace.
2. Same as option 1, but add zoning (whole house is currently one zone).
3. Install an oil-fired boiler, outdoor reset, hydronic furnace for the first floor (in basement, using existing ducts), and hydronic furnace for the second floor (in attic, using existing ducts). Possibly incorporate indirect hot water (vs. electric now).

Which one would you pick, given my design goals?

Notes:
- Sticking with oil as the fuel (not switching to propane)
- Sticking with forced air as distribution method

Thanks!

STEVEusaPA

Maybe the best options is to just stick with the properly sized furnace. They are making 2 stage oil fired furnaces, but that wouldn't help for your range. They also make condensing furnaces...but I wouldn't want one. Modern furnace, modern energy saving components.
I would stick with one zone, but I would first check to make sure the duct work is correct-properly sized, have TESP (Total External Static Pressure) checked, especially so the AC is properly sized and can deliver the comfort (de-humidification).
I think switching to a boiler, and hydro air would be the most expensive choice, with no comfort benefits. Oil boiler, with outdoor reset, and essential 2 zones (plus indirect), would short cycle and probably have a higher operating cost. Even though making domestic hot water would probably be cheaper with oil & indirect, I don't think its a good idea, unless you're adding radiant, or snow melt (a lot more expense, and a more advanced design, controls, etc.)
I also don't think zoning the air is a good option either. Unless your house is divided up in such a way (and insulated between the zones) where you can thermally isolate each zone. Otherwise, heat moves to cold and you're short cycling on one zone. Properly sized, properly balanced duct work would give you the best performance in your situation, in my opinion.

EBEBRATT-Ed

I agreewith @STEVEusaPA If it ain't broke don't fix it. I am a boiler guy but if your system works and heats evenly Install a new furnace. 80,000 btus sounds fine for your square footage so your heat loss seems right.

Many would recommend Thermopride as one of the better oil furnaces

HVACNUT

Agree with all from above.
Some furnaces offer a Carlin 2 stage burner.
Hot air heat is a dry heat, so also think about a steam humidifier. If your able to run a new thermostat wire, you can get a thermostat that will act as a humidistat as well. Otherwise, it goes in the return duct.

mculik5

Makes sense. Thanks for the comments.

Kybeans403

Couple questions:

Is there AC currently?

Ductwork set up....IE...do you have a supply plenum running from furnace up to attic and vents in ceiling? Any returns upstairs (assuming 2 floors)

Or....are upper floors heater with low, sidewall registers?

How many occupants in house? Demands of bathrooms...

Hot water can be taken care of with hybrid style electric heat pump water heater....,requires 30 amp, 220v dedicated circuit, and as long as there are no spa style tubs etc.. unit can run on HP for majority of the time and provide dehimidification to basement.....peak demands may require electric elements being energized but at least in my experience a "normal" home with average shower times and temps works just fine with HP.

Is current furnace a High or low boy?

John Mills_5

Heat is heat as far as drying the air out. Air dries because cold air, which may be humid, infiltrates and is heated. Warm air can hold lots more moisture so even though no moisture is being removed by radiation or a forced air furnace, the relative humidity is drastically lowered. So I fully disagree that forced air is a dry heat. The family home with a converted gravity system and leaky as can be could have humidity as low as 15% with 2 console humidifers blasting. Compare that to a new, tight house with forced air and it could need dehumidification year round or some kind of ventilation to keep the humidity down since cold air isn't leaking in.

heathead

Hybrid System ??? Replace the the oil furnace with oil furnace but add Heat-pump to the system. Heat-pump runs when its above 40 and oil heat runs below 40. That temperature could change depending upon fuel cost and electric rate.

CapeCodOilGuy

I'm with Steve PA. The simplest solution would be a new furnace (I'd recommend a Williamson, with a Carlin EZ-1 burner and 70200 primary control). Their heat exchangers are built like tanks and will last longer than anything else on the market. Hydro-Air does give you flexibility and allows you to have an indirect water heater and cold-start control, but it's an expensive installation, especially if you want to zone it. Often, the perfect is the enemy of the simple and reliable.

mikeg2015

heathead said:

Hybrid System ??? Replace the the oil furnace with oil furnace but add Heat-pump to the system. Heat-pump runs when its above 40 and oil heat runs below 40. That temperature could change depending upon fuel cost and electric rate.

^^^ this. If you have AC, or want to add AC, unless you have a hot water system with a mod con, a heat pump should always be in the mix. It's cheaper to operate in most locations above 45F than even a 97% gas furnace. that might be 1/3 of the BTU's needed for the whole season.

With oil, it should be automatic. It's probably cheaper to operate down to around 15-20, which is probably 75% of the heating requirement for the season.

I'd get a new oil furnace, but add a heat pump PROPERLY (probably 90+% of AC system in the US are oversized, sometimes by 2x) sized for cooling capacity. It should hold on it's own down to 30-40F then the furnace takes over.

The bonus is the heat is very even and a 80k furnace with maybe a 3 ton heat pump gives you a 50% turndown ratio in capacity, so more even heating.


I have a 2x 2 ton output heat pumps on my home with 172k BTU of steam radiation, so not running the boiler above 40F keeps things much more even. heat loss is around 95k, so the two heat pumps keep up just fine with about 40k combined output at that point. Energy cost is about 30% lower on average above 40F than steam boiler at around 80% efficiency.

mikeg2015

One more thing, with the cost of oil, you might look at a inverter drive heat pump, that can prodice heat at a lower temp and more economical overall. Then a very small boiler can supplement it with a hot water coil and/or with baseboards.

There's a descent argument for hydro air because you can run the heat pump below the thermal balance point, all the way down to the economic balance point. Plus boilers last longer. You can also add some hot water baseboard at some point to supplement. This isn't a bad idea for the 1st floor, so you balance the airflow on the furnace for cooling loads and locate the thermostat upstairs, then run hot water to add heat downstairs during the day when occupied.

also with a boiler you can have 2 heat pump units as an option for zoning.

Finally as mentioned, zoning is easy with hot water.

If you go hydronic, consider a reverse cycle chiller as another option. But for simplicity, a heat pump is cheap.