ChrisInCT
New Member
Hello All,
Complete novice here - so please bear with my attempts at working through some of this math. I glommed on to some other threads and tried to use a yearlong fuel consumption approach to figure out what my heat load requirements are. I might be way off base here. Was hoping that someone can confirm my math or point out the error (or many errors!!!) of my ways. I am waiting for the first quotes to come in on a boiler replacement and want to be prepared to confirm or pushback on any quotes received.
Thirty year old home in Connecticut, zip=06410, 2100 sqft with an oil fired boiler, how water baseboard system that needs to be replaced. Three zones, one for each of the two floors and a third for an indirect water heater. Home has been resided and all windows have been replaced, insulation is good. A couple of years ago we went through an energy assessment and beyond some minor weather-stripping, we got a good bill of health. The current boiler system is a "Magic Heat" - what a name! And I think the model is DM122, a bit hard to read on the placard. What I could read was a stated 89% efficiency, but I doubt it’s achieving that today. The heat exchanger is cracked and the entire unit itself is quite hot - a ton of heat loss - when it fires up.
So, following some other threads I got the heating degree days at 6244 for my location and a 99% design temp of +6F for my location. I used 1168 gallons of oil over the past year. I used that data to calc the following:
Does this suggest that I need a unit with 51KBTUs? Any suggestions on units that would effectively and efficiently work given these figures? Appreciate any feedback at all!
-Chris
Complete novice here - so please bear with my attempts at working through some of this math. I glommed on to some other threads and tried to use a yearlong fuel consumption approach to figure out what my heat load requirements are. I might be way off base here. Was hoping that someone can confirm my math or point out the error (or many errors!!!) of my ways. I am waiting for the first quotes to come in on a boiler replacement and want to be prepared to confirm or pushback on any quotes received.
Thirty year old home in Connecticut, zip=06410, 2100 sqft with an oil fired boiler, how water baseboard system that needs to be replaced. Three zones, one for each of the two floors and a third for an indirect water heater. Home has been resided and all windows have been replaced, insulation is good. A couple of years ago we went through an energy assessment and beyond some minor weather-stripping, we got a good bill of health. The current boiler system is a "Magic Heat" - what a name! And I think the model is DM122, a bit hard to read on the placard. What I could read was a stated 89% efficiency, but I doubt it’s achieving that today. The heat exchanger is cracked and the entire unit itself is quite hot - a ton of heat loss - when it fires up.
So, following some other threads I got the heating degree days at 6244 for my location and a 99% design temp of +6F for my location. I used 1168 gallons of oil over the past year. I used that data to calc the following:
Item | Value | Source or Calculation | |
Oil BTU | 138,000 | from another thread | |
Current Efficiency | 80% | a lower guess than what my system suggests | |
Effective BTUs | 110,400 | oil BTUs * .80 | |
Gallons Used | 1,168 | actual value | |
Gallons / HDD | 0.19 | gallons / 6244 HDD | |
BTU / HDD Day | 20651.38 | above result * effective BTUs | |
BTU / HDD Hour | 860.47 | above result per hour | |
Design Temp | 6 | ||
Heating Degrees | 59 | ||
Heat Load | 50,768 | BTU / HDD Hour * 59 |
Does this suggest that I need a unit with 51KBTUs? Any suggestions on units that would effectively and efficiently work given these figures? Appreciate any feedback at all!
-Chris