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Hi folks.
I am working on a room addition bid and don’t know how to determine if the existing heating system will handle the extra space. Radiant hot water in a twenty two hundred square foot ranch- finished basement included- built in late sixties. flat ceilings everywhere- don’t know about the r-value throughout but house is insulated.
Addition is 24×28 vaulted ceiling- extensive glazing.
current boiler has a 150thou btu input w/120thou output
addition is on the East side of home
I will be insulating r-19 walls, r-38 ceilings, r-30 floors.
I am worried that the add on will push system past it’s limits- nothing to base that on- just a guess
any advice to help determine heating need?
thanks
Replies
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Not a scientific reply but our 3,400 sq/ft house is handled by a 93,900 btu natural gas boiler.
Two hotwater baseboard loops (main floor and basement), each served by its own circulator and thermostat.
The house is a 1950's era Ranch that was custom built with good material but not necessarily insulated to today's standards.
Most boiler installations seem to be oversized.
My guess is the present boiler should be able to handle the additional load.
Does the boiler have a manifold setup that would make it easy to add another zone ?
*hi Alan.yes it has a manifold. Seems like a lot to ask from an existing system.I appreciate your input. let you know what I find out...
*Why doesn't anyone state their location (which implies climate, design temperature, etc)? So I'll pull a design temp of 10F out the air. I'd guesmiate a heat load on the old structure of 80,000 BTU/hour (+-50%) and of the new addition of 12,000 BTU/hour if you keep the construction reasonably tight.Does the homeowner have old utility bills? You could look at the worst case winter month on record and see what the average fuel consumption was then. If it was less than 88,000 BTU/hout input (70,000 BTU/hour output) I'd feel comfortable hanging the new addition on the current system. That works out to 630 therms/month. If the homeowner didn't keep records, the gas company may have.You could put a timer on the current system for a few days ( buy an hour meter from Graingers or wire an old electro-mechanical clock in parallel with one of the blowers or some other 120-volt part of the heating system). If the average outside temp was 30F (diff = 70-30= 40F) and your design temp is 10 (diff = 70-10=60F), then you will need 60/40 x the run hours to keep the current house warm at your design temprature. Those hours should be less than 24. If they are under 24 by a fair margin, then it has the additional capacity you are looking for. -David
*Hi, David -Thanks for your technical reply - this is very practical information even if I'm not the orginal poster of this thread.(It will be added to my stack of printouts.)To take advantage of this opportunity... I want to monitor the temperature of the supply and return water to the boiler and would like to be nudged toward a brand/setup for this.I know the gauges (usually analog dial types with round glass face) are usually threaded into a special fitting that is added to the line but not sure if there is one superior design over another. The temperature range of the gauge would probably be between 0 and 250 F ?This will be part of a simple bypass piping I'm wanting to add for bringing up the temperature of the return before it enters the boiler.I will start another thread if you think this is distracting from the original post.By the way, I am in Zone 6/7, probably more Zone 6. :-)I guess this information is standard practice in Plot Notes.Alan
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Hi folks.
I am working on a room addition bid and don't know how to determine if the existing heating system will handle the extra space. Radiant hot water in a twenty two hundred square foot ranch- finished basement included- built in late sixties. flat ceilings everywhere- don't know about the r-value throughout but house is insulated.
Addition is 24x28 vaulted ceiling- extensive glazing.
current boiler has a 150thou btu input w/120thou output
addition is on the East side of home
I will be insulating r-19 walls, r-38 ceilings, r-30 floors.
I am worried that the add on will push system past it's limits- nothing to base that on- just a guess
any advice to help determine heating need?
thanks