Climate Control

Proper heating/cooling and ventilation are critical to your comfort. This section will help you to shape your requirements so you can interact effectively with surveyors, heating engineers, suppliers and builders so you end up with a solution which meets your goals and it is cost effective. Heating is an old discipline (going as far back as the Roman times) and various sophisticated techniques (and jargon!) have evolved over time. To help you we have developed a short Heating Primer and a Heating Glossary. These are focused on medium-to-large residences. We rarely get involved in installing residential heating, cooling and ventilation systems (but can do if you want to). Instead, we are frequently asked to retro-fit our lifestyle controls into existing systems. And if the system does not perform (insufficient heat capacity, poor heat distribution, etc.), we find ourselves trying to "debug" a poorly conceived central heating system. Thus yet again, some clear thinking up front may save considerable hardship later.

A well-design heating/cooling system impacts energy consumption and thus running costs. A poorly designed system can end up costing twice as much to run and in a large residence this can be a material amount. Further, the Guidance Note GPG302 produced by the Building Research Energy Conservation Support Unit (BRECSU) on behalf of the Energy Efficiency Programme states that you can save up to 17% of your heating bill with a good control system alone.

Comfort Requirements

There are various ways to heat a residence: with radiators, via under floor heating or through air conditioning. In addition you can also have open (gas) fires. If your objective is to cool down (a must in southern Europe) then you really have to use air conditioning (plus perhaps, ceiling fans). All of which can be controlled remotely - but before you investigate the different options think first about your comfort requirements.

First, think about how you will use the space when you are in residence. How cold does it get in Winter?. How hot does it get in Summer?. Do you normally use the whole house or just the ground floor and a wing? This may help you to define your heating zones (refer to our Heating Primer). Do you have full time service personnel or staff? If so, they probably will have their own heating zone. Are there any spaces with special heating, cooling or ventilation requirements? A pool? A wine cellar? A basement room that gets too humid? Or a study stuffed with computer equipment that gets too hot? Or a sound insulated music room that it is too well insulated? Or perhaps a south facing room, attic or conservatory which gets too much sun? All these point to different heating zones and heating/cooling requirements.

Think also of your requirements when you are away. At minimum you need frost control (so the system turns itself on, if temperature drops below a set minimum) but, do you have valuables (paintings, books) that may get damaged if temperature or humidity drops or raises? Does hot water need to be available for washing / cleaning even when you are away?

These are some of the questions you need to reflect on before calling the experts. Even if you already have a system installed, these notes may help you to verify that your installation covers all eventualities.

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Heating Methods

There are essentially three ways to heat a residence: radiators/convectors, under floor heating and through air conditioning (also referred as warm air or forced hot air systems). We have excluded electric heaters because their inefficiency and thus their are rarely used in residences. The table below summarizes the advantages and disadvantages of the main 3 types:

Once you have established your requirements, it is relatively easy to set out your maximum heating and cooling needs for each room/zone. Engineers work this out by establishing the conductive heat loss in each room and ventilation loss (see the Heating Glossary) for a set target temperature. This will result on a heating requirement for each room.

For cooling, you follow a similar process but this time you add all the heat gains - which includes the heat gains through the walls (as above) plus any electrical equipment (lights, electronic equipment, amplifiers, etc.) and heat emitted by the people in the room. This will result in a cooling requirement for the room.

Heating and cooling requirements (plus any special requirements such as pools, cellars, etc.) will determine the best system or combination of systems and thus your heating/cooling plan.

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Sensors and Thermostats

In a fully automated heating/cooling system, the thermostats and other controlling equipment is connected to the actual heating/cooling equipment as if the Main Control Unit did not exist - thus in the event that the Main Control Unit (or its link) is removed or fails, the controlled heating / cooling is still available [the same principle is applied to lighting control and security control].

The various thermostats are then connected to the Main Control Unit to provide the additional flexibility and ease of control you need. In this arrangement, the Main Control Unit can now alter the program and set points dynamically and can pass on any user commands from any touch screens or remote panels. It can also interrogate the status of the heating/cooling system.

The additional flexibility allows you to pre-program relatively complex logic so the the system can perform functions automatically, for instance:

• automatically setting default programs for different seasons, taking action if windows or doors have been left open (the Main Control Unit just may let temperature drop) or switching the heating/ventilation off in the event of a fire or smoke alarm.

Or allowing you to access heating control remotely, for instance:

• setting the heating on from work, in preparation for your arrival or turning the heating off, if you forgot, etc.

To accomplish this, the thermostats have to have some sort of connectivity to the Main Control Unit. The most common (and so far, best) way to do this is to use a standard (full- or half-duplex) RS-485 protocol (see for instance Aprilaire or Residential Control Systems) but proprietary protocols and "voltage signal" protocols (where communication happens by just on/off signals given limited remote control) can also be used. These units are referred as "communicating thermostats".

The thermostat will connect then to the temperature sensors (indoor, outdoor) and humidity sensors. Most communicating thermostats will allow up to four (or more) sensors and can process the sensor data so they only respond to the maximum, minimum or average readings. In most cases the sensors can also be connected remotely from the thermostat.

This also suggests how lifestyle control can be easily retrofitted to existing heating systems. Either connect the Main Control Unit to the appropriate thermostat(s) (if they have communication capability) or simply replace the existing thermostats. There is no need to touch the central heating/cooling system (unless it has been misdesigned!).

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Noise

A final point on HVAC systems: noise. There are many sources of unpleasant and uncomfortable noise in a heating/cooling system: the boiler firing, pipes cracking as they expand or contract, pumps operating, fans spinning, air circulating in ducts, etc. A well designed system should eliminate or minimize all of these and we can help you in achieving an almost silent operation. See our section on noise for further details.

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