The objective of this article is to introduce the heating and cooling systems mostly used in Cyprus. It describes in detail the technical data, initial cost, running cost, efficiency, advantages and disadvantages of each system. Concerning heating installation, electric and hydronic radiant floor heating are partially described and concerning cooling, air conditioning systems such as Split unit, VRV or Fan coil units has been taken under study.

HEATING

In floor or else under-floor heating systems are the best choice if the priority of the homeowner is to have the most comfortable environment inside the house. Heat is slowly transferred from the floor to the air unlike to other units which are relied on forced air. This fact results to a better air quality and increased comfort. Also the system is quiet and “invisible” (no radiators, ducts or holes).
When considering radiant floor heating for your home, there are two popular types to consider: Electric and Hydronic. This report breaks down the benefits and disadvantages of each with consideration of cost and energy efficiency.

Electric radiant under-floor heating

For heating a small zoned space like a single bedroom or bathroom, electric in-floor heating is usually a good choice because Electric systems use few components and are simple to install. But this system cannot be used as the primary heating source because the running costs are very high when calculated over a period of time.

Benefits:

• The installation process is simple and ideal for remodel projects
• Initial cost and Labor costs are minimal
• On-demand heating is zoned for specific rooms
• Heating can run on a timer

Disadvantages:

• Uses a large amount of electricity resulting to expensive energy bills
• Primarily designed for comfort in small zones, not as primary heating source

Hydronic radiant under-floor heating

Another method for in-floor heating relies on hot water instead of electricity. Hydronic radiant heating is ideal for homeowners that like consistent heat year round, as it operates very efficiently and keeps the home at a consistent, comfortable temperature. Hydronic systems are ideal for homes that already use a water heater as that energy can be efficiently diverted into the floor. In hydronic radiant floor systems, heated water is pumped from a heat source (boiler, heat pump) through a network of tubing underneath the floor.

Benefits:

• Floor slab becomes one big heated mass for gentle, pleasant warmth
• Structure of the house holds the heat inside
• Heat remains constant for long periods of time
• Once mass of home has reached desired temperature, minimal energy is required to maintain it
• Energy savings / 60% less running costs than electric radiant

Disadvantages:

• Initial cost and Labor costs for installation are higher than electric systems
• System is more complex and not ideal for small zones
• Not ideal for homeowners that like to turn heat on and off at different times of day

COOLING

 The primary purpose of the air conditioning system is to maintain the thermal comfort of the people inside the living space. In this section three different units are presented which are used for residential cooling purposes.

Split Unit AC systems

Split type air conditioning systems are one-to-one systems consisting of one evaporator unit connected to an external condensing unit. Both the indoor and outdoor  units are connected through copper tubing and electrical cabling. The indoor part (evaporator) pulls heat out from the surrounding air while the outdoor  condensing unit transfers the heat into the environment. Can be used for both heating and cooling.

Advantages:

• Low initial cost
• Ease of installation
• Suitable for small zones

Disadvantages:

• There is limitation on the distance between the indoor and outdoor unit (30 meter)
• Maintenance (cleaning/change of filters) is within the occupied space
• Limited air throw which can lead to possible hot/cold spots
• Impact on building aesthetics of large building because too many outdoor units will spoil the appearance of the building
• Non space efficient

VRV Split Unit AC systems

Variable Refrigerant Volume (VRV) is an air-condition system configuration where there is one outdoor condensing unit and multiple indoor units. The term variable refrigerant flow refers to the ability of the system to control multiple evaporators (indoor units), enabling the use of many evaporator of differing capacities and configurations connected to a single condensing unit (outdoor unit). The arrangement provides an individualized comfort control, and simultaneous heating and cooling in different zones.

Benefits:

• Saves energy / 30% lower running cost than split unit
• Conserves space (one outside unit many indoor units)

• The extended maximum piping length gives more flexibility when designing the system.

• Outdoor units can be placed on the roof where they have no effect on the design of the building interior
• Units are designed to operate quietly

• Units are controlled in each individual room, so local malfunctions does not cause the entire system to shut down
• Ease of installation

Disadvantages:

• High initial cost
• System is more complex and not ideal for small zones
• Maintenance (cleaning/change of filters) is within the occupied space

Air-Water Heat pump

Heat pump is an HVAC system configuration where there is one outdoor condensing unit and multiple indoor units. The arrangement provides an individualized comfort control, and simultaneous heating and cooling in different zones.

Benefits:

• Saves energy / 45% lower running cost than split unit
• Conserves space (one outside unit many indoor units)

• The extended maximum piping length gives more flexibility when designing the system.

• Outdoor units can be placed on the roof where they have no effect on the design of the building interior

Disadvantages:

• High initial cost
• System is more complex and not ideal for small zones
• Not a very quiet system

Combination of heating and cooling systems for a 200 m2 house

I. Electric radiant under-floor for heating and Split unit systems for cooling

Estimated initial cost and labor costs for installation = 15000 euros (8500 Electric radiant under-floor & 6500 Split units)
Estimated maximum running cost per year = 4500 euros (3200 for heating and 1300 for cooling)

II. Hydronic radiant under-floor for heating combined with VRV systems for cooling

Estimated initial cost and labor costs for installation = 30000 euros (10000 Hydronic radiant under-floor & 20000 VRV system with hydroboxes)
Estimated maximum running cost per year = 1800 euros (950 for heating and 850 for cooling)

III. Hydronic radiant under-floor for heating combined with Heat pump system for cooling (recommended)

Estimated initial cost and labor costs for installation = 25000 euros (10000 Hydronic radiant under-floor and 15000 air-water heat pump with fan coil indoor units)
Estimated maximum running cost per year = 1600 euros (950 for heating and 650 for cooling)