# How to calculate degree day units

## Calculating Degree Days

Last edited Nov 26, 2008 12: Different plants have a different base temperature above which they will start to grow, and their growth will typically be roughly proportional to the amount by which that base temperature is exceeded.

First, Thanks!

Investing Futures. In other words if, through regression analysis, you find the optimal base temperature of both buildings, you should find that the base temperature of Building B is lower than the base temperature of Building A.

## What Are Heating and Cooling Degree Days

The Handle With Care article has a bit more on this. Doing these things won't make your degree-day data any more accurate, but it will make it clear that degree-day-based analysis of energy consumption is unavoidably approximate, and that the approximation method used to calculate the degree days is typically only one of many sources of inaccuracy.

If it's a mean value calculated from good, regular readings, the resulting degree days when the outside temperature doesn't cross the base temperature will be identical to those calculated using the Integration Method.

Of course more people might complain that it's too hot , but that's a different story. For weather stations that are shown with a bar and stars see right - all the airport ICAO and WMO stations and the higher-quality personal weather stations - we use detailed temperature readings taken throughout each day, turning them into degree days using the Integration Method that is explained in this Google Knol about degree days.

## Degree Day Calculation

Thank you for a very informative and easy to read article. Dave Horrigan. Andy Cunningham.

Thanks for any help on this. Well done in taking time and using rigourous terms to define. For HDD they subtract the average temperature from the base temperature taking zero if the average temperature is greater than the base temperature on that day.

## Heating Degree Day - HDD

We think it makes a lot more sense for Degree Days. Google sends me an email when somebody comments on this knol, but it seems they don't when somebody writes a comment under a comment.

But upgrading a weather station from the Enhanced Met Office Method to the Integration Method is more than just a small tweak, and it can result in noticeable recalculation differences.

Thanks for all your thoughts and wisdom! That said, we don't want to suggest that it's necessary to re-generate previously-collected data after a station's upgrade to the Integration Method.

But you might find that you can improve the correlation a little if you give the experimental approach a go and try correlating your energy consumption with HDD with base temperatures around that point. No offence intended to the insulation industry - Jock just tends to be a little quick to point the finger...

Last edited Aug 18, 2008 7: Web Tool Desktop App: Laura McLoughlin. The explanation is very dense, however. With this optimized database of detailed temperature data it was finally practical for us calculate degree days live using the Integration Method.

We call that the Mean Temperature Method.