Getting the most bang for my buck

firsthome

Hello,





I purchased a home two years ago with a 1950’s Kohler 22

boiler with a carlin burner and taco recirculation pump. The Kohler also has a

domestic hot water supply attached to it that is tank less. There is one zone

in the system. At the recent cleaning the technician measured 78% efficiency at

the chimney. I have no problems with the system currently so I am not going to

replace it yet to gain another 10-15% of efficiency. I have two questions

though.





1 We burn approximately 1 tank 275 gals of oil for dhw from

May to September. Given the current oil price.





Should I consider shutting off the boiler for those months

and replacing with a traditional or hybrid electric hot water heater?





We have a well, temp is too low for on demand, and gas is

not available here.





In your experience would this effect the boiler that is past

its prime?





2 The basement is finished with approx 10’ of baseboard heat

to heat the room 21Lx14Wx7h I know that it is undersized and at the end of the

heating run.





Should I add another zone to this old system?





Or leave it alone and deal with the cool basement that we

don’t use often in the winter? I will upgrade when we replace the boiler

eventually.





In your experience would this effect the boiler that is past

its prime?

John Mills_5

Efficiency

Remember, there are 2 efficiency numbers thrown around out there. Combustion efficiency is what your tech is measuring. That means once warmed up fully, the combustion process is 78% efficient in keeping the heat in the boiler. Don't confuse that  number with annual efficiency which is what you see on new boilers. Annual efficiency or AFUE tells what % of the heat produced heats the house over the entire season. So going to a new 85% AFUE boiler over your existing may not seem like much of an improvement, in reality it is. Your oldie could be as low as 55% efficient wasting a lot of fuel warming up, cooling down and during the off cycle.



What is your cost per gallon of oil? What is cost per kwh of juice? That will tell if abandoning the tankless makes sense.

firsthome

reply thank you john

John,

Thank you for the reply is there any way to determine the current efficiency of my system?



I have heard from several contractors that it is probably only 50%

efficient. How do they determine that?



One contractor that was giving me

the hard sell said it might be 30%.



I know those are just estimates but

I would like to compare apples to apples the cost of a new system

versus my current system.



I would like this to determine a cost benefit analysis for a new system.



Kohler "22" fc-6



110,000 BTU 1.45 gal hr



175 degree h2o



400 sqft steam/hot water





I know we should not discuss installation prices but here are my numbers for a 1700sf raised ranch with a walkout basement and 2 bedrooms 1 bath over a crawlspace.













 

oil used

avg price

 

total cost

total degree

days





Total

2009-2010

1081.6

2.7775

 

$3,007.67

3930





Total

2010-2011

948.7

3.308143

 

3086.732

4064





 

 

 

 

 

 





CLP

$0.11723 per KWh

 

 

 

 



My 2011 is not over yet so hdd will increase through the end of the month.



Kohler "22" fc-6

110,000 BTU 1.45 gal hr

175 degree h2o

400 sqft steam/hot water

Robert O'Brien

A proper setup

will knock 300,maybe 400 gallons off that 1100 gals/year. Call it $3.50/gallon = $1050-1300/ year,even assuming no inflation or rise in heating oil costs,that's $10,500-13,000 over 10 years

firsthome

Thank you Rob

A proper setup

will knock 300,maybe 400 gallons off that 1100 gals/year. Call it

$3.50/gallon = $1050-1300/ year,even assuming no inflation or rise in

heating oil costs,that's $10,500-13,000 over 10 years



By shutting off the boiler during the summer I will save approximately 300 gallons per year. Buying an electric water heater, install and power for the first summer will be $1000-1300. After the first year $300 each subsequent year for power only. Using your estimation I would save $6200-8700 over 10 years



Am I missing something or is this the better way to go?

Techman

What?

What is the 110,000 btu and 1.45 gph, for?

Robert O'Brien

1Kwh= 3413 BTU

Or at 11.2 cents/kwh, $4.59 for the same 140K BTU in a gallon of oil. You're underestimating the cost of the electricity. The oil unit has eff losses which are substantial but still only bring it down to the $3/gallon equivalent range

BobC

GE Hybird

A friend of mine installed a GE Hybird (heat pump) hot water heater last spring and was very happy with the drop in his electric bill (vacation home in NH, elec costs about 0.18 per KWH). He calculated that hot water heater would pay for itself in 5 years (it costs about 3-4X what a regular HWH costs) and it's warrantied for 10years so it really was a no brainier for him.



Bob

Ironman

You May Want To Re-Consider

If your numbers of 1.45 gph and 110,000 btu are from the boiler tag, then your boiler was 54% efficient when it was brand new and clean. You're probably under 50% now. That means for every $1.00 you spend on fuel oil, 50 cents is being wasted up your chimney!



A new boiler would save you 40% or more on fuel if properly installed and set up with outdoor reset.



The Buderus GB125E is over 90% efficient before outdoor reset is factored in. Couple it with a hot water indirect tank and you'll have a very efficient system that should last 40+ years and cut your consumption way down.



With a 1700sq. ft. home, you should be able to use a boiler that's well under 100k btu's. Your current one is 203kbtu, if firing @ 1.45 gph.