My existing dishwasher is really old so I was thinking it might be a good idea to replace it. It uses:
- 14 gallons of water / cycle (from the manual)
- 25 loads / month
- 4,200 gallons per year
I looked up a new Bosch washer (~$500):
- 3.2 gallons / wash (could use 2.9 - 7 depending on factors)
- 25 loads / month
- 960 gallons per year
Additionally, with my antique washer we have to pre-rinse some things. Consumer Reports said pre-rinsing uses like 6,000 gallons / year, so we'll go with that, but for us I think that is reeeally high.
Assumptions:
- New washer will have a 7 year life
-
Water costs $5.16 / 748 gallons (This includes variable sewer costs)
Old Dishwasher New Dishwasher Wash Water 4,200 960 Pre-Rinse 6,000 0 Total Gal. 10,200 960 Cost $70.36 $6.62 Cost (7 yrs) $492 $46.36 Difference $446
I haven't quantified energy costs to heat the water at this point, but it would only be the wash water as we don't use hot water to rinse dishes off quickly.
It looks like it makes sense to buy a cheap dishwasher but:
- This is using Bosch's 3.2 gallons / cycle rating. It could very well use more water (7 gallons). The calculation using 7 gallons / cycle brings the savings down to $391 over 7 years.
- The 6,000 gallons for pre-washing seems high for what we do. My sink does <3 gallons / minute of water, but at 3 gpm that 6,000 gallons is >5 minutes of washing / day. Our pre-rinsing isn't that long. If we use only 3,000 gallons, then that brings it down to a savings of only $301 over 7 years.
- If the new washer uses 7 gallons / cycle, plus we reduce pre-rinsing to 3,000 gallons, that makes the savings $246 over 7 years.
Besides energy costs, what else am I missing?
Is the 7 years of life too short?
Is the energy costs going to be a game changer?
July 25, 2018 at 10:06AM
