back up heat for mini split system

[Helen]

Wow! Thank you all for all of this info.
My heating degree days are 3687 with 0.3% est. and based on the community slightly inland from me which is therefore slightly colder in the winter. I am located on a point surrounded by the Bay of Fundy essentially- St Andrews New Brunswick Canada.

[AC_Hacker]

Originally Posted by Helen

Wow! Thank you all for all of this info.
My heating degree days are 3687 with 0.3% est. and based on the community slightly inland from me which is therefore slightly colder in the winter. I am located on a point surrounded by the Bay of Fundy essentially- St Andrews New Brunswick Canada.

OK, great... did you check the "Celsius" or the "Fahrenheit" button on the interface? It makes a really big difference...

For instance, my mild-winter heating degree days in Fahrenheit average is 4816, but my Celsius heating degree days average is 1874... same weather, different system.

By the way, the "0.3% est" means that the database from which your heating degree days was calculated, was missing a very small amount of data (0.3%) and statistical 'guessing' was done to fill in the missing data. In other words, your calculated value is very highly accurate.

-AC_Hacker

[Helen]

My heating degree days are 3687. I replied earlier but must have done it incorrectly as I can't see my message! Sorry.
Is this helpful?
Helen

[Helen]

Sorry for my mix up!
I did use celsius. What does all of this mean?
H

[AC_Hacker]

Originally Posted by Helen

Sorry for my mix up!
I did use Celsius. What does all of this mean?
H

This from Wikipedia:

Heating degree day (HDD) is a measurement designed to reflect the demand for energy needed to heat a building. It is derived from measurements of outside air temperature. The heating requirements for a given structure at a specific location are considered to be directly proportional to the number of HDD at that location. A similar measurement, cooling degree day (CDD), reflects the amount of energy used to cool a home or business.

There are also maps with HDD values on them that would help people to determine their HDD if they did not want to be more accurate and go to the HDD website calculator.

So if you gave this information to people who understood Heating Degree Days, and not everyone on this blog understands the concept, then they could give more useful recommendations to you regarding heating and insulation, rather than just guessing what might be... in particular, if your Heating Degree Days closely matched someone else's HDD value, their advice might be more appropriate to your situation.

But it must be in the same units, Fahrenheit or Celsius, to have any meaning.

-AC

[Xringer]

HDD data is sometimes used by heating oil stock traders to calculate what oil sales might be in a general area.

Just remember, since HDDs are "derived from measurements of outside air temperature",
and doesn't factor in solar gain from south facing windows.
So, if you have 5 or 6 windows that give good solar gain, HDD numbers might not be very useful.

A well sealed & insulated house that gets good solar gain, that's equipped
with low night-loss thermal barriers on all it's windows, will save a lot of money on heating cost.


If you had three of these..

They would give you more than 12,000 BTHh (using 3.6kw).
In my home, that's going to keep our pipes for freezing and allow us to stay healthy for a while.
But, if it goes down to -5F for a week, we will be using some solid fuel or heating oil too..

If that -5F week occurred with a grid failure, it would be 100% solid fuel usage.