shayneyasinski wrote:as you know most boiler units ask for a btu requirement when selecting a unit and this has me stumped.shayne
What you want is a heat loss calculation on the building you are trying to heat. It will take into account the building size, construction, windows, doors, geographic location and orientation, etc. Depending on the level of detail it will give you heat requirements in BTU per hour for each room and/or the entire building. The most accurate analysis uses a "Manual J" calculation. This is one of many manuals used in the heating and air conditioning (HVAC) trade to design systems. There is an abridged version that's a less complicated and easier to understand. It uses an Excel spreadsheet to make the calculations. Even the abridged version has an above average learning curve but it will give accurate results for both heating and air conditioning.
Do you want to do this analysis yourself? If your home is a typical residence you could get some price quotes for a new heating system and use their numbers. Installation contractors frequently use "rule of thumb" analysis that work for typical jobs based on their installation experience. If there is anything atypical get a complete analysis. Expect to pay for a Manual J calculation done by a professional.