Digital programmable thermostats at Northgate

Introduction

Those of you who attended our last annual meeting at Buzz Aldrin Elementary School may remember when talk centered on digital programmable thermostats. The discussion continued at the last board meeting and has resulted in the board recommending that Northgate begin transitioning from it's inefficient, analog, non-programmable thermostats, to newer, much more energy-efficient and accurate digital, programmable (and non-programmable) thermostats. We project some real cost savings from the purchase and correct use of these thermostats.

In this article, we'll discuss our current thermostats, their inefficiencies, and the added costs we incur in using them. We'll then talk about the modern thermostats we are transitioning to, and their benefits. Finally, we'll deal with the costs to have them installed, the savings to the Northgate community and the timetable this will happen under.

Before we continue on, we should say that this transition will be entirely optional. Of course, we would realize much greater savings if all owners transitioned. The Association will handle all of the scheduling, purchase, and installation aspects. Owners simply agree to the transition and make a full payment for the thermostat prior to installation. Please note that while this will be optional, old analog thermostats will no longer be made available as replacements for failed thermostats. If your thermostat fails, it will be replaced with your choice of one of three digital thermostats (to be discussed below). The good news is, not only will this result in shared savings to the Northgate community, but the cost will be cheaper than if you were to replace your failed unit with an older analog one.

But first we will answer a few questions you may have.

Q: Why are we looking at replacing our thermostats? They work just fine.

A: Although they appear to work well, the truth is, because of their outdated design, they are very inaccurate and inefficient. The result is higher than normal utility bills and an uncomfortable living environment. See more on this topic below.

Q: If I want to replace my thermostat, can't I just head down to a hardware supply store to buy one?

A: No. Neither Home Depot nor Lowes carry the type of thermostat our HVAC systems require. Read more directly below to find out why.

Our current thermostats

The HVAC system employed at Northgate is 40 years old and was very popular at a time when energy was plentiful and cheap. Technically, we have what is called a single pipe, fan coil system. Water is heated or chilled in our utility building, piped throughout the Northgate complex, into our buildings and through our individual units . The pipes go through a radiator type coil (similar to car radiators), and air is forcibly passed over the whole assembly. The fan-driven heated or cooled air is then sent through the ducting system and into the vents in each individual room. The temperature in your unit is achieved by cycling on and off the blower motor. The more frequently the motor is turned on, the warmer (or cooler) your unit becomes.

Our thermostats run at line voltage (120v) and must be able to turn the relay on an electric motor on or off, which explains why you cannot purchase these at major hardware stores - they are not stocked. Because of this unique, and now rare design, thermostats that are made for our systems are difficult to find. Through some amount of research, we have found a company in Pennsylvania that makes digital programmable thermostats for fan coil systems. We will buy directly from them and make their thermostats available to Northgate owners at bulk rates.

Most likely, you currently have one of two brands of thermostat - a Honeywell or a Whites Rodgers. The units are rectangular, have either a dial or a lever to set the temperature, and are based on a technology that was invented close to 100 years ago. Because the technology is so old and the components so inaccurate, when you set your unit to be, say 70°F, it may heat (or cool) your unit to within a range of 8 degrees. In other words, you may get as high as 74° or as low as 66°. This large variance may result in higher utility bills as higher demands (as much as 4°) can be placed on our heating/cooling infrastructure. If you want your unit to be 70°, and you get 66°, your comfort level is impacted, most likely resulting in you turning up the thermostat to achieve satisfaction.

The greater inaccuracy also results in your blower motor powering up on less frequent, but longer lasting cycles, placing undue strain on the HVAC system. Studies have shown that thermostats that cycle heat (or cold) more frequently and for less time cumultatively add less strain to the type of industrial sized chillers or boilers in use at Northgate.

So five major benefits are gained from moving to newer, more advanced thermostats:

  1. 15% energy savings just from the greater accuracy thermostats
  2. Another 10% potential savings if the programmable thermostats are used correctly
  3. More stable temperatures resulting in a greater comfort level
  4. Less strain on our HVAC infrastructure (boiler and chiller)
  5. Cheaper replacement thermostats

New digital thermostats

In the last 20 years, circuit boards and electronic temperature sensors have taken over the design of thermostats and have enabled them to be extremely accurate (to within a range of +/- 1°). In addition, user chosen settings can be stored in non-volatile memory, allowing the thermostats to retain these values even through power outages.

There are 3 types of thermostats -- those that can be programmed to turn the the heating/cooling on or off at pre-determined times of the day (programmable), those that are programmable AND can be re-programmed using a wireless remote control and those that are set at, and maintain one temperature (non-programmable).

Programmable thermostatsT202 Programmable thermostat

The programmable thermostats we will be purchasing (seen in the image to the right) allow the homeowner to choose from 2 different time schedules -- a 7 day schedule where the times are shared among all days, and a 5-2 day schedule where distinct times are shared among the 5 business days, and different times are shared for the 2 weekend days. This latter schedule would be appropriate for users who work during the business week and take the weekend off. Despite the schedule chosen, each day is divided into 4 time zones (Wake, Leave, Home, Sleep) with the thermostat heating or cooling the unit to a set temperature for the duration of each zone. Each of these zones may be temporarily overridden in case the users schedule changes or the user temporarily requires more heat (or cool).

Typical usage for an owner who must leave their condo for work would be as follows: If the owner wakes at 7 a.m., they would set the thermostat Wake time for 6:30 a.m. to allow sufficient time for the condo to warm or cool to the desired temperature. The temperatue would stay at that temperature until it reached the next time zone. If the user leaves for work at 8:30, they would program the Leave zone to start at 8:30. From this time until the user returns home, the thermostat would maintain that set temperature.

To realize cost savings, presumably a temperature would be chosen for the Leave zone that would be lower (in the winter) or higher (in the summer). If the user feels comfortable at 72° in the winter, a possible temperature setting for the unit during the time the unit is unoccupied would be 67° -- this of course would modified if the resident has pets. If the user returns home at 5:30 p.m., they would program the unit to again return the condo to a comfortable temperature at 5:00 p.m. The temperature for this zone would then be in effect until the user goes to bed. By programming the thermostat to reduce it's power usage during times when the user is away from their condo, or in bed, energy is saved, with the savings being passed onto the entire community.

To achieve these savings, it is imperative that a programmable thermostat be correctly used. The EPA offers the following advice for programmable usage:

  1. Keep the temperature set at its energy savings set-points for long periods of time (at least eight hours), for example, during the day, when no one is at home, and through the night, after bedtime.
  2. All thermostats let you temporarily make an area warmer or cooler, without erasing the pre-set programming. This override is cancelled automatically at the next program period. You use more energy (and end up paying more on energy bills) if you consistently “hold” or over-ride the pre-programmed settings.
  3. Units typically have two types of hold features: (a) hold/permanent/vacation; (b) temporary. Avoid using the hold/permanent/vacation feature to manage day to day temperature settings. “Hold” or “vacation” features are best when you're planning to be away for an extended period. Set this feature at a constant, efficient temperature (i.e. several degrees warmer temperature in summer, several degrees cooler during winter), when going away for the weekend or on vacation. You'll waste energy and money if you leave the “hold” feature at the comfort setting while you're away.
  4. Cranking your unit up to 90 degrees or down to 40 degrees, for example, will not heat or cool your house any faster. Most thermostats begin to heat or cool at a set time, to reach setpoint temperatures sometime thereafter. Units with adaptive (smart/intelligent) recovery features are an exception to this rule — Adaptive recovery units are constantly calculating the amount of time required to heat or cool the house, so that it reaches that temperature when the homeowner programmed it. By "examining" the performance of the past few days the thermostat can keep track of the seasons. In this way, your house is always at the comfort levels when occupied, but saving the most energy when unoccupied.1

See more information at the product information page.

Non-programmable thermostats

In addition to making digital programmable thermostats available to Northgate residents, we will also make digital non-programmable thermostats available for purchase. Unlike programmable thermostats, non-programmable thermostats, as the name implies, cannot be programmed. The user sets the thermostat to one desired temperature, and that temperature is maintained 24 hours a day. This would obviously be an inefficient way of using a thermostat. We encourage all users who choose non-programmable thermostats to make an effort to manually turn down (or up) the thermostat when leaving their units for extended periods.

Beyond not being programmable, these thermostats resemble programmable thermostats in every way -- they are digital, accurate and carry the same advantages. These will be the most affordable of the three thermostats we will be offering.

See more information at the product information page.

Wireless programmable thermostats

These thermostats are basically the same as the Programmable thermostats, only there is a remote control included that allows the user to remotely modify the temperature in the condo. This thermostat system comes with the following components:

Thermostat-Transmitter:

Displays room temperature, system mode, time of day, and maintains the programming events. The thermostat-transmitter senses the room temperature and sends a pre-coded signal to the receiver. The signal will transmit up to 150 ft in open space.

Control-Receiver:

Continuously looks for the coded signal sent from the thermostat-transmitter. The control-receiver is wired to the heating and cooling system. It can be mounted external from the system or at the location of the old thermostat. The control has indicator LED’s that show systems operation.

See more information at the product information page.

 

Costs

Owners will be given the opportunity to purchase one of three thermostats at discounted rates (Prices INCLUDE installation). 

Thermostat pricing
Thermostat type Unit + Installation
Programmable thermostats $115.00
Non-programmable thermostats $118.00
Wireless programmable thermostats $152.00