Converting from oil to gas heat

Hello everyone..I just bought a house and I am converting over to gas heat before this winter hits...I'm trying to get as many opinions that I can regarding the type of boiler I should get. I cannot power vent because of the regulations being to close to the window. The boilers I am considering is the

1. Alpine forced hot water 105,000 BTU...96% for $3173 with $1220 back in rebates

2. Forced hot water HE Natural Draft 105,000 BTU..ES24NI-G..85% for $1915 with $830 back in rebates

3. Standard forced series 2..130,000 BTU...205NIL-GEl2...82% for $2015 with $860 back in rebates


I believe I can go up my chimney with a liner with all these boilers. I just ask what boiler should I go with to save the most money and be an effective boiler. Been reading posts about the alpine with the LCD board could be an expensive fix if it breaks..also not to mention my oiler burner now is only 4 years old so I will probably sell for around $1000 so I can take that money into consideration when purchasing my new boiler....thank-you

 

Hi Nick, I'm east of you in Maine where we depend highly on oil for heat and only recently has natural gas become available in a few locations so I get your question a lot.

You didn't say natural gas or propane?

Replacing a 4 year old oil heating system will rarely result in a reasonable payback. Lots of numbers would need to be crunched, but probably over 10 years to recoup what you spend. IMO, better options for heating will be available in 10 years.

In any case, all the units you listed are very large, which indicates a very large home or one that could use some energy efficiency improvements. Example: If you cut your energy use in half that new heating system will be much smaller, but might not be needed.

Being a new home, the first step would be to locate previous fuel use data. Then do some investigating around the house and tell us how well the place is insulated. Is this an old home that has been flipped or a new home and how big?

My point is, energy improvements first, and heating system last if it can still be justified.

At 4 years old it should be running at about 86% efficiency. Those 90+% efficiency units rarely reach that number so maybe a net of 88% to 90%. A 4% improvement in fuel use amounts to almost nothing, lost in the seasonal variations. Improve your air leakage and insulation and maybe 40% less fuel with the system you have. Now, you would notice that, both in savings and comfort.

Bud

 

Before you do anything, do a heat loss calculation, a manual J, to determine the correct size heating system. Too big costs you money in fuel and equipment.

You can direct vent most through a regular chimney - if it is dedicated. You run a double wall sleeve inside it.

 

I converted my home to natural gas from oil and saw a saving of 1000 Canadian about what I saved on the price of the fuel . The oil boiler is a New Yorker fired at 0.75 and a steady state efficiency of 94%, my own boiler control to prevent condensing and the gas a Viessamnn Viodent 100 condensing. On a 10f day the Viessamnn produces about one liter of condensate per cubic meter of gas burnt . If the oil keeps going down I may be firing the oil back up.

 

Thanks...it's natural gas....well I was getting a larger unit 105,000 because I will also run a gas stove...fireplace...dryer..outdoor BBQ..and boiler...my plumber added up the units and did a formula and I think came up with 80,000 Btu's for everything..I'm just wondering if going with the alpine is worth it for $1000 more

 

Nick, I'm totally confused by your explanation of how the boiler size was chosen.

What have the other appliances got to do with sizing the boiler?

Sorry, that's all wrong.

Bud asked, you didn't answer, please do:

Also, please tell us the square footage of the home. This can give us a 'sanity check' of the boiler sizing numbers.

A boiler of 100K BTUH is usually enough to heat a 3000 SQ FT home.

You're not ready to select any boiler yet...

 

Yea sorry to confuse all the other appliances were to figure out my size of gas meter...my plumber dId the square footage and said I needed about 80,000 BTU...my square footage is about 1900...the ES2 boiler only makes a 70K or 105K....the alpine makes an 80K and a 105K

 

Well... 80K is probably a bit much for your home. That's a bit over 40 BTUH / Square foot and it's unlikely your heat loss is that high.

Are you upstate? or down closer to Joisey? (just to get an idea of your climate)

If someone actually did a careful calculation I bet you would find that 70K was even a bit more than you need.

 

I'm on Long Island...not sure how the plumber came up with 80k....he divided my square footage by something...if I was going with the series 2 boiler they have a 96k and the next one was 130k..so u think the 105k is definitely to much

 

So the plumber used a rule of thumb.....not good. My main level is 1,200 sq. last year during our 0* week in north jersey I used roughly 32,000 BTUh. You're probably closer to 60,000 than 80,000 and 105,000 is waaaay too much.

 

So what size boiler do u have....I have to check but the oil one that is 4 years old is I think 120k...wonder why they put that size boiler in

 

I use the rule of thumb as a 'sanity check' only. It's not a substitute for a proper estimate.

It's a drafty leaky old Victorian that needs as much as 40 BTUH/SF. MOST homes come in around 25-35 with the majority leaning toward the 25 end of the scale.

Given that, your home is probably between 50K and 70K.

I think so, but what I think is no substitute for an actual heat loss estimate.

 

Probably because they replaced it with the same size they took out.

And because they aren't paying the bills.

And because they don't really care.

 

So let me ask everyone's opinion. Should I go for the burnham alpine boiler 96% 80k BTU for $1750 or the burnham ES2 series 85% 105K BTU for $1085. Is it really worth or that much of a money saving difference in the 96% compared to the 85%? I will purchasing my new gas boiler in the upcoming week and want to get everyone's feedback again. Thanks Nick

 

The efficiency of 96% is only going to happen if the system can consistently return water at 90 degrees f, they neglect to mention that fact and that 90f is hard to accomplish with fin tube baseboard.

 

Let's say " less than 135F, the lower the better "

This is because most homes with baseboard are designed with only enough baseboard to heat the home on the coldest days with 180F water. Therefore, it is not possible to heat the home with cool enough water that will allow a condensing boiler to condense for more than a small portion of the heating season. Once the return water to the boiler is over 135F the boiler will no longer condense and the extra efficiency at that point goes up the chimney, just like a conventional non-condensing boiler.

Include in this discussion the fact that a condensing boiler requires more annual maintenance which could (and usually does) amount to a couple / few hundred dollars a year.

Me, personally, would go with a good quality conventional cast iron boiler. Your mileage may vary.

 

But if I'm going to choose between these 2...do u think 96% is much better then the 85%...or the 85% will be fine and I won't save that much money between the two....u seem to have a lot of knowledge on this so that's why I am asking...thanks

 

I guess what I'm trying to say is that unless you have an over-abundance of heat emitters, i.e. baseboards/radiators, that would be able to adequately heat your home with lower temperature water, you aren't going to gain the benefit of the higher efficiency.

In other words, once a condensing boiler STOPS condensing because the home requires hotter water to maintain the heat, and the return water comes back above 135F, all of the 'extra' efficiency is lost. The efficiency of a condensing boiler when it's NOT condensing is more or less the same as a conventional boiler.

You aren't going to see the higher percentage of efficiency for the entire heating season.

As I said, me personally would choose a conventional cast iron boiler UNLESS the heat emitters were designed to operate with lower temperature water for the entire (or the large majority of the) heating season.

IMO, it simply doesn't make sense to spend the extra money on a condensing boiler if you don't have a heat emitter system that is designed to heat the home with lower temperature water.