“In Having the Fizz Without the Guilt, the NY Times reviews home water carbonation systems. Most of them seemed like reasonable, even frugal systems for getting carbonated water at home. But consider this one:
When price is no object, home versions of soda fountains are available from several companies. The one I tried was the Everpure Exubera, an Italian appliance that must be installed by a plumber. It sells for $2,600 plus about $1,000 for a faucet, along with cartridges that cost $100 and are good for 30 gallons of seltzer. (A water filter is extra.) The carbonation is infinitely adjustable. It can make tiny and delicate bubbles or large and bold ones. The equipment fits under the kitchen sink or in a cabinet; the faucet sits next to the regular faucet or in a wet bar. More information is available at residential.everpure.com. … Eventually, even the Exubera should pay for itself.
I doubt this will ever pay for itself. That’s over $3 for each gallon of seltzer, compared with about $1 at my super market. That’s a high price, even for a machine that let’s you control bubble size and temperature. A better alternative for the heavy seltzer drinker is to bottle their own water using a home made carbonator. You can buy the carbonator and regulator attachment for $40 and a huge tank good for less than a hundred, refill it for just a 18 bucks and which is good for 500 gallons. Something interesting I learned from this website, “To carbonate a bottle of water, you must pre-chill the water first, because the solubility of CO2 in water is greatly increased by both lowering the temperature (Le Chatelier’s principle), and by raising the pressure of the CO2 gas (Henry’s law)””