I got two 44,000btu 2 stage 80% furnaces in my attic and the downstairs basically heats the whole house. Just had our freezing weather and just one furnace heated the whole house and yes it ran and ran. The first stage will keep the house at 70 degrees downstairs and 75 upstairs. If on the second stage the downstairs will do 75 degrees over time. The issue with that is the up stairs will get 77+ degrees up stairs in the main hallway but the bedrooms if doors closed will remain cool at 70-73. I just run the fan to try to evenly distribute that hallway heat since the upstairs return is in that hallway. The upstairs furnace wasn’t used at all, I just kicked on the blower motor fan. These are both new HVAC systems. I sized and bought the equipment myself. I did increase the upstairs 2.5 ton condenser to a 3 ton condenser due to the fact this is Texas and we run the AC more upstairs since the heat rises. I also added another return and put it in the master bedroom to compensate for the extra air needed. I chose not to do furnace media filters because I wanted to install 3 inch media filters in all my return grills. The bonus is that it keeps the ducts clean and has a .30 static pressure on a MERV 10 and they will last 6 months to a year. I also increased the power of the ECM variable blower motors. I like to feel the air stream coming out the vents. The system is extremely quiet and I’m getting 1200 CFM airflow upstairs and 1000 CFM downstairs. I almost got a 66,000 BTU furnace for the downstairs and was thinking I should have until watching your video that it running most of the coldest days is a good thing.
They wrote up a contract for a furnace that seemed too small. That is because all they know is square ft. It should be CUBIC feet, to recognize that 12 ft or cathedral ceilings require more air to be heated. They raised the size and over the last few years, the cycle time seems to be ideal.
Good Subject! 1:Sealed and insulated my house, now my furnace is too big.!! 2: "Furnace Creep" Every time it's replaced they just put in a larger one "to be safe", Well, after the third one it's way too big.
I very little money for NEW boiler. I have a single zone 90,000 BTU oil hot water boiler. The only furnace that I can buy is a used 126,000 BTU oil furnace. Does that mean I can't use that furnace? I am on a waiting list for housing and can't invest any money in this house. It's a 3 bedroom ranch.
I own an HVAC company, but I can give you a pretty good idea, if you answer a group of questions. Where do you live location wise? (Zone of the country makes a difference), Are you looking to replace the AC or Heat pump? I would assume it is a 4-5-ton unit, if you want upgraded AC or Heat Pump setup. But a 60k btu furnace is pretty small for a 2400 sq ft house in any zoned area of the United States. Is that all above grade or does that include the basement? (If you have a basement). A Manual J load calculation really needs to be done; we can get really close. Does you have natural gas, electric or LP? Where is your furnace located in your home? What part of your home faces the South? Once I know what part of the country, I will know more about your humidity levels as latent heat is a big deal. If it is the original 2004 furnace, 60k Btu's was undersized to start with. But we cannot just go throwing in a 120k Btu, 2200CFM system, as your ducts were never made to take that kind of airflow. However, if you said your equipment is in the attic and you live in a ranch style home, all your supply and return ducts can be upgraded, insulation upgraded (blown-in cellulose), etc etc. Depending on if you plan on replacing the AC or not, and other questions and answers will fill in some of the blanks. 80k-100k Btu with a modulating gas valve with a variable speed blower fan will probably be the ticket.
@@Balticblue93 My house originally had a 100K 80%. It is in Detroit. The installer stated a 96% putting out 60K will be fine. The south facing side has a walkout basement. The furnace sits in the western side of the home or rear center of the basement. The furnace is 5 years old. The a/c is 1.5 years old. When the temperature is less than 20 degrees, the furnace always stays on. We keep the air supply flews closed going to the basement and laundry room.
I often wonder about sizing? a 4 ton heat pump which offers 48,000 btus, good for 1600 cfm. and if gas it has 80,000 btus. so lets here from the so called contractors out there...
Your furnace should never run all day, that means it's under sized , 2 stage is common even in 80% where in the heck did you come up with this garbage, like comment below furnace and duct must be sized together along with matching blower to the ac tonnage . You have no business trying to educate people in HVAC. I would like to see you properly size a system.
He's talking about the coldest 1% time of the year that it will run the majority of the day if sized properly. Makes perfect sense. Same for HVAC sizing in the summer months. People that oversize have cooler open room areas but other closed door rooms in the house can feel warmer because it doesn't stay on as long and humidity builds up in them. Oversizing is bad because it shortens life of system due to chronic short cycling. All systems should be sized properly or even undersized slightly for optimal cooling comfort all throughout home. You have to size it based on average temperatures in your area. Never size on the abnormally hot or cold days otherwise your system will be very inefficient the majority of the year when you're at your average highs and the life of it will be shortened and will be more prone to constant repairs. I've seen many compressers fail within 5 years due to oversizing in hot, humid climates.
@@jph77 Shows how much technology can change in 4 years With todays technology oversized system short cycling is a thing of the past. like in my case, a 4-ton was too small in the extreme triple digit temps of the summer my 4 ton system ran constantly and didn't remove humidity worth a flip but ran normal cycles in the milder months. Then there's other side of that coin a 5-ton was too big in the cooler months and would drop the temps too fast and would only run 5 mins at a time if that so how do you fix that you may ask? Simple do like i did and get a 5-ton two-stage 18 seer American Standard heat pump with a variable speed air handler. And voila my short cycling problem was solved. Big 2nd stage 5-ton capacity for them 100° plus triple digit hot as heck summer days and then the smaller 1st stage 3.5 to 4-ton (whatever 65% Capacity of 5 tons are) capacity for those milder 70-90° days. And as an added bonus it cut my electric usage down by more than half because now it doesn't run for hours on end during the hottest days of the summer. Most hvac contractors dont like setups like that and dont recommend them because it causes less breakdowns and is 1000 times more efficient than a single stage system thats either gonna be too much or not work to cool for crap.
@@Brad.W Correct! 2 stage with variable speed air handler does help some in extreme conditions. Just make sure that the original venting is sized correctly to handle the excess pressure in those extreme situations when at full power or issues can arise. I was referring to the fact that most people have single stage systems because of the huge price differences and on those you can't oversize due to short cycling. 90% of calls I go on are mainly single stage systems where they are oversized. We do give options for customers most of them don't want to pay the price. You can though use a single stage system that is zoned and it will act like a variable speed when both zones are calling and can actually work pretty good. It just needs to be slightly oversized and it will pull from both returns whether one zone is running or both are running and humidity wouldn't be an issue. This is really the only time you can get away with oversizing on a single stage and be comfortable in extreme conditions. Last year we installed a Bosch IDS 2.0 system in ours that is zoned. Inverter technology is the future of HVAC systems. They're very quiet and super energy efficient! Nearly 21 seer! I predict that in the future that most popular HVAC brands will adapt to inverter technology.
@@jph77 yeah i had to run a new duct line to a room that was unvented and increase the return grille to keep it from sounding like a jet engine everytime it goes full capacity.
Proper sizing of the furnace is very important, also very important is sizing of the duct system. Thanks for the video!
I got two 44,000btu 2 stage 80% furnaces in my attic and the downstairs basically heats the whole house. Just had our freezing weather and just one furnace heated the whole house and yes it ran and ran. The first stage will keep the house at 70 degrees downstairs and 75 upstairs. If on the second stage the downstairs will do 75 degrees over time. The issue with that is the up stairs will get 77+ degrees up stairs in the main hallway but the bedrooms if doors closed will remain cool at 70-73. I just run the fan to try to evenly distribute that hallway heat since the upstairs return is in that hallway. The upstairs furnace wasn’t used at all, I just kicked on the blower motor fan.
These are both new HVAC systems. I sized and bought the equipment myself. I did increase the upstairs 2.5 ton condenser to a 3 ton condenser due to the fact this is Texas and we run the AC more upstairs since the heat rises. I also added another return and put it in the master bedroom to compensate for the extra air needed. I chose not to do furnace media filters because I wanted to install 3 inch media filters in all my return grills. The bonus is that it keeps the ducts clean and has a .30 static pressure on a MERV 10 and they will last 6 months to a year. I also increased the power of the ECM variable blower motors. I like to feel the air stream coming out the vents. The system is extremely quiet and I’m getting 1200 CFM airflow upstairs and 1000 CFM downstairs. I almost got a 66,000 BTU furnace for the downstairs and was thinking I should have until watching your video that it running most of the coldest days is a good thing.
They wrote up a contract for a furnace that seemed too small. That is because all they know is square ft. It should be CUBIC feet, to recognize that 12 ft or cathedral ceilings require more air to be heated. They raised the size and over the last few years, the cycle time seems to be ideal.
I keep my furnace on the lowest fan speed. It's 80k but, and on high speed, it can heat up my house like an oven so quickly.
Good Subject!
1:Sealed and insulated my house, now my furnace is too big.!!
2: "Furnace Creep" Every time it's replaced they just put in a larger one "to be safe", Well, after the third one it's way too big.
I very little money for NEW boiler. I have a single zone 90,000 BTU oil hot water boiler. The only furnace that I can buy is a used 126,000 BTU oil furnace. Does that mean I can't use that furnace? I am on a waiting list for housing and can't invest any money in this house. It's a 3 bedroom ranch.
Well how many btu/sf would be a properly sized furnace?
it is not done by sq ft - need a load calculation!
I have a 2400 square foot home built in 2003. The furnace stays on all of the time. It does not cycle. It is 60K.
maybe an 80000 btu would be better ?
I own an HVAC company, but I can give you a pretty good idea, if you answer a group of questions. Where do you live location wise? (Zone of the country makes a difference), Are you looking to replace the AC or Heat pump? I would assume it is a 4-5-ton unit, if you want upgraded AC or Heat Pump setup. But a 60k btu furnace is pretty small for a 2400 sq ft house in any zoned area of the United States. Is that all above grade or does that include the basement? (If you have a basement). A Manual J load calculation really needs to be done; we can get really close. Does you have natural gas, electric or LP? Where is your furnace located in your home? What part of your home faces the South? Once I know what part of the country, I will know more about your humidity levels as latent heat is a big deal. If it is the original 2004 furnace, 60k Btu's was undersized to start with. But we cannot just go throwing in a 120k Btu, 2200CFM system, as your ducts were never made to take that kind of airflow. However, if you said your equipment is in the attic and you live in a ranch style home, all your supply and return ducts can be upgraded, insulation upgraded (blown-in cellulose), etc etc. Depending on if you plan on replacing the AC or not, and other questions and answers will fill in some of the blanks. 80k-100k Btu with a modulating gas valve with a variable speed blower fan will probably be the ticket.
@@Balticblue93 My house originally had a 100K 80%. It is in Detroit. The installer stated a 96% putting out 60K will be fine. The south facing side has a walkout basement. The furnace sits in the western side of the home or rear center of the basement. The furnace is 5 years old. The a/c is 1.5 years old. When the temperature is less than 20 degrees, the furnace always stays on. We keep the air supply flews closed going to the basement and laundry room.
That makes too much sense
I often wonder about sizing? a 4 ton heat pump which offers 48,000 btus, good for 1600 cfm. and if gas it has 80,000 btus. so lets here from the so called contractors out there...
Your furnace should never run all day, that means it's under sized , 2 stage is common even in 80% where in the heck did you come up with this garbage, like comment below furnace and duct must be sized together along with matching blower to the ac tonnage . You have no business trying to educate people in HVAC. I would like to see you properly size a system.
He's talking about the coldest 1% time of the year that it will run the majority of the day if sized properly. Makes perfect sense.
Same for HVAC sizing in the summer months. People that oversize have cooler open room areas but other closed door rooms in the house can feel warmer because it doesn't stay on as long and humidity builds up in them.
Oversizing is bad because it shortens life of system due to chronic short cycling. All systems should be sized properly or even undersized slightly for optimal cooling comfort all throughout home.
You have to size it based on average temperatures in your area. Never size on the abnormally hot or cold days otherwise your system will be very inefficient the majority of the year when you're at your average highs and the life of it will be shortened and will be more prone to constant repairs.
I've seen many compressers fail within 5 years due to oversizing in hot, humid climates.
@@jph77 Shows how much technology can change in 4 years With todays technology oversized system short cycling is a thing of the past. like in my case, a 4-ton was too small in the extreme triple digit temps of the summer my 4 ton system ran constantly and didn't remove humidity worth a flip but ran normal cycles in the milder months. Then there's other side of that coin a 5-ton was too big in the cooler months and would drop the temps too fast and would only run 5 mins at a time if that so how do you fix that you may ask? Simple do like i did and get a 5-ton two-stage 18 seer American Standard heat pump with a variable speed air handler. And voila my short cycling problem was solved. Big 2nd stage 5-ton capacity for them 100° plus triple digit hot as heck summer days and then the smaller 1st stage 3.5 to 4-ton (whatever 65% Capacity of 5 tons are) capacity for those milder 70-90° days. And as an added bonus it cut my electric usage down by more than half because now it doesn't run for hours on end during the hottest days of the summer. Most hvac contractors dont like setups like that and dont recommend them because it causes less breakdowns and is 1000 times more efficient than a single stage system thats either gonna be too much or not work to cool for crap.
@@Brad.W Correct! 2 stage with variable speed air handler does help some in extreme conditions. Just make sure that the original venting is sized correctly to handle the excess pressure in those extreme situations when at full power or issues can arise.
I was referring to the fact that most people have single stage systems because of the huge price differences and on those you can't oversize due to short cycling. 90% of calls I go on are mainly single stage systems where they are oversized. We do give options for customers most of them don't want to pay the price.
You can though use a single stage system that is zoned and it will act like a variable speed when both zones are calling and can actually work pretty good. It just needs to be slightly oversized and it will pull from both returns whether one zone is running or both are running and humidity wouldn't be an issue. This is really the only time you can get away with oversizing on a single stage and be comfortable in extreme conditions.
Last year we installed a Bosch IDS 2.0 system in ours that is zoned. Inverter technology is the future of HVAC systems. They're very quiet and super energy efficient! Nearly 21 seer!
I predict that in the future that most popular HVAC brands will adapt to inverter technology.
@@jph77 yeah i had to run a new duct line to a room that was unvented and increase the return grille to keep it from sounding like a jet engine everytime it goes full capacity.
@@Brad.W yep...and restricted air flow won't distribute evenly throughout house.