Friday, July 6, 2007

Zoning For The Poor

Poor people pay more, it is often said. Let's see what would be an average cost of a DIY zoning system assembled out of components specifically intended for DIY applications. Let's make following assumptions:

  • We're dealing with an average family with two kids, geek parents who spend some time working home therefore four bedroom house (fourth bedroom being the office), two bathroom, dining room, family room, laundry room - total of 9 zones (that'll be a pessimistic estimate);
  • All the components will be bought through Smarthome;
  • Functionality will try to mimic what DZ offers today.
Let's see how much is this going to cost us at today's prices....

HVAC 4 Zone Controller - Rs485 - $349.99, power supply sold separately - that's just four zones, out of nine required;

Alternatively, HVAC 4-Zone Controller - $229.99, plus power supply - $11.99;

Thermostat Display Unit - $199.99, one per zone;

Or, as an alternative, wall mounted temperature sensor - $99.99 per zone, plus LCD Wall Display Unit - on sale for $107.99, for all four zones;

6-In Normally Open 24V AC Duct Damper or 6-In Normally Closed 24-VAC Damper- $59.99 (or, if you're feeling generous, 6 Inch Diameter Damper Normally Closed for low, low cost of $98.99 - I don't see much difference);

X10 Universal Module for $22.99 or Appliance Module for $34.99, depending on your configuration, one per damper;

Now, all the stuff above is just the beginning, but it'll be enough for a ballpark: the cheap version of the above for 4 zones will cost you, depending on components, anywhere between 973.86 and 1685.87 plus tax, shipping and handling.

For 9 zones (ignoring the fact that a 9 zone controller is not being sold, and counting only extra cost for dampers and sensors), the prices will be 1888.71 and 3355.72, respectively.

That is, not including cabling and insallation.

Oh, and that gives you only a bang-bang version using unreliable by design X10 protocol. Forget about remote control and monitoring.

For comparizon, DZ installation for the same physical configuration will cost you:

  • Anywhere from $50 for a beaten up 10 year old computer to $400 for a shiny new one to run the control system on (with web access, remote control and monitoring and unlimited number of zones);
  • Roughly $50 to $100 for 1-Wire adapter and servo controller, depending on source and capabilities;
  • $10 to $15 per zone plus some manual labor for modulating dampers;
  • About $3 a zone for a 1-Wire temperature sensor.
All of the above amounts to $152 to $552 for 4 zone system, and $217 to $617 for a 9 zone system (difference being primarily the price of the computer and servo controller).

Take your pick.

Update: Forgot to include cost of 1-Wire adapter and servo controller into DZ installation cost. Fixed.

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