OK back.... we had a broken electric HWS which was costing us a fortune in electricity, gave us 2 minute showers and we had to wait at least 30 mins in between, it took 90 mins to half fill the bath.... anyhoo we got the instant gas, we figured it only heats water when we are actually using it and it never runs out. this is lame but we literally get out of the shower every morning and say "I love this water heater" .... go for instant gas you'll never look back. it was a bit exy but we had to get an indoor one (we live in an apartment) and I'm pretty sure the outdoor ones are cheaper.