Hello

I am new to Solar Water Heater Usage, my house has 6 people and i plan to install solar water heater.
can i know, during the day the sun will heat up the water and water will be hot. When we reach home at night and start showers, the hot water will be utilised and cold water will going into the tank mixing the cold and hot water, will this reduce the water temperature as no more sun light? So to heat up the water I will need to switch on the electric heating element?

how long will it take to warm up the water again?

Thanks

It depends on the size of your water heater storage tank.
Yours is how many liters?

If night time the water gets colder then you can switch on electricity to warm up the water

5minute shower consumes 80 liter of water
assume you use 100 liter x 6 person x 2 times a day
100*6*2 = 1200liters

most solar heater can store 150-300liter

if 300 liter is considered, or 3 x 100liter bath of 10minute
savings = 30min x 4kw or 2kwh/per day
or RM1/day

i am looking at 200 to 300 liters solar heater
meaning after 3 person shower, i need switch on the heating
how long will it take to heat up again?
so every night need switch on if more than 3 people shower
also no sun to heat up

I believe your electric bill will go sky high because need to heat up the large 200-300L tank every day. Also must remember during rainy season you will depend totally on electricity.
Haven't factor in work to clean up so that can maintain efficiency.
I think you better go for normal electric heater unless you don't mine all the cost and hassle

I have been using SolarMate in my house for the last 11 years. Only on 2 occasions that we needed to switch on the backup heater (3KW- which is lower than most if not all Instant Shower Heater).
Family size is 4. The hot water is still very HOT!

estimated 100 litres per shower i think is OK but out of the 100 litres may b 40% only is hot water, so 40L.

300L / 40L = 7.5 showers at night only bcoz no sun light, but as you use hot water, cold water will be pumped into the solar, so water will get colder. So usually i assume 50L per person so 300L / 50L = 6 showers, this is if you solar has sufficient sun light during the day time.

If you are using Tube solar like Aquasolar V66, water temperature will be higher and hence mix less hot water, estimated 30% hot, 70% cold. u get 30L per shower. add 10L to account temperature drop. 300L / 40L = 7 - 8 showers.

this is just estimation based on good weather.

If hot day outside can shower 6 to 7 without need to on heater if continuous showering
If another person back late at night need to on heater as cold water is mix with hot dy. water temp willl go down due to earlier people showering

Yep, using hot water at night will mix in cold water and cool things down. The electric element will kick in to reheat, usually taking about 20-30 minutes to warm the tank back up.