All you need to know is your gas consumption in summer and the consumers number (50l for a person). For example, if there are four consumers and the monthly gas bill doesn’t exceed AMD 8000 then you need a 200l solar waer heater. If there are five consumers and monthly bill for natural gas is less than AMD 10000 then a 250l water heater would be your choice. For 6-7 consumers we recommend to buy a 300l model and for more consumers we can design an individual project for your house. If you have questions feel free to call us on +374 91 192818.