How much oil does it take to heat the water to do one load of laundry in a front load washer?

Question

I have been doing my laundry in cold water and it's really not doing anything for them as far as freshness. I would much prefer to wash in warm. We have oil heat/hot water. Is there a way to determine an approximate ounce-age of oil it takes to warm the wash water?

Answer 1

It is next to impossible to give you a really accurate number without some specific details, including: size of washing machine, number of fills/cycles per load, water temperatures, is the water heated during both the wash and rinse cycles, etc.......

However, here is a sample calculation to give you a ROUGH idea:

Assume:

washer uses 75 liters/load (75 kg)

water is heated from 22 deg. C to 55 deg. C

water is heated entirely through oil (no electric heat in washer)

heating value of oil is 10,000 cal/gram (41,868 J/gram)

water heater efficiency of 80%

Then:

Heat required to raise total water temperature is:

Q=c(m)delta T

Q=4.186 J/(gram-deg C) x 75 kg x 1000 g/kg x (55-22) deg. C

Q= 10,360,350 Joules

Therefore at a heat of combustion of 41,868 J/gram and an efficiency of 80%, your hot water heater will need:

m = 10,360,350 J/gram / [41,868 J/gram x 0.8]

m = 309 grams of oil (or 0.309 kg or 0.681 lbs or 10.9 oz [avdp])

REMEMBER: this is just a rough estimate.

Once you know more information you can run through the calculation yourself.