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1 What is a deep building renovation?

Deep renovation is the idea of capturing the full economic energy efficiency potential of your building with focus on building fabric. It leads to remarkable energy savings. As nearly all of Latvia’s stock of multifamily residential buildings continues to rapidly deteriorate due to harsh weather conditions and lack of proper maintenance, this idea is attractive.

In a deep renovation all elements of your building are addressed, leading to:

  • Reduced energy consumption – you will need less energy to heat your home; 
  • Better temperature control – you will be able to control the temperature in each room of your apartment; 
  • Improved comfort life conditions – you will enjoy suitable temperature and indoor air quality. Also noise coming in from traffic and outdoor activities is reduced; 
  • Improved health: different studies shows that energy efficiency projects improving indoor comfort conditions translates in considerable savings on health bills; 
  • Lower capital expenditure – a more efficient, well-insulated building needs smaller or no emergency repairs; 
  • Good investment - as your building’s value and attractiveness will increase.

Deep renovation also links to another important aspect: the long term preservation of the building. The implementation of an energy efficiency measures without taking care of all important building elements, like for example: roof, foundations, staircases, balconies, heating and domestic hot water systems is a short sighted plan.

In simpler words, energy efficiency without deep renovation is a lost opportunity and sometimes also a waste of money. Therefore, handbook only advocates deep renovation, where buildings are holistically assessed and renovated.

Energy efficiency alone cannot solve the structural problem affecting the majority of the multifamily resident’s buildings in Latvia. Internal heating networks, foundations, balconies, staircases, roofs needs to be addressed to provide good and acceptable living standards.

Building fabric

The building fabric refers to the roofs, walls, windows, floors and doors of your building. It plays the leading role in the energy efficiency of a structure and must be carefully considered in the design and planning phase of a deep renovation. Building’s heating requirements are greatly influenced by the building fabric choices and their heat transfer characteristics.

Realizing the full economic energy efficiency potential of your buildings requires designing, financing and implementing energy efficiency investments. Energy efficiency is measured by understanding the annual energy needs of your building, the thermal insulation and characteristic of the building fabric and the requirements for ventilation. The heat transfer coefficient (U-value) is a measure of thermal conductivity[1]; meaning the lower it is for a given construction material, the better the thermal insulation property are. So for example: a meter thick brick walls has the same thermal insulation properties than 10cm thermal insulation board.

Currently, the U-value of the external walls of the first mass series building developments of the 1960s to 1995s in Latvia is in the range of 1 - 1.58 W/ K m² that is 3 to 5 times higher than the values specified in the regulatory requirements under the current building code. Thus, the thermal rehabilitation of existing buildings is a necessary measure, which can enable considerable energy savings.

The heating system

Most of the existing multifamily residential building in Latvia, which are targeted by handbook, are equipped with one-pipe heating systems without by-pass for flow control. These systems are most of the time outdated and needs substantial improvements. For renovating these systems there are two main options:

  • The retrofit of the heating system using the same one pipe configuration,
  • The installation of a two pipe systems with horizontal heat distribution to the flats.

In most of the case the retrofit of the heating system using a one-pipe configuration is recommended, because it enables good control and heat distribution with more affordable investment costs. The main limitation is metering, as individual heat metering by flats is not possible.

Independently from the system configuration, when renovating a heating system all main distribution pipes in the basement and technical attic have to be insulated using ad-hoc technical insulation solutions. Then the system must include the installation of thermostatic radiators valves and suitable balancing valves for even temperature distribution throughout the building.

Domestic hot water system

Most of the existing multifamily residential buildings in Latvia are equipped with a centralised domestic hot water systems. The circulation loop of these systems are also used for space heating of the bathroom. The systems are often in rather poor technical conditions with substantial heat losses.

In a deep building renovation project this system is renovated; and there are several solutions:

  • The existing system is decommissioned. Bathroom towel heaters are connected to the space heating system and a new domestic hot water system is installed. The new system is planned minimising pipe diameters and length of the circulation loop. This aims at minimizing building energy consumption.
  • The existing system is retrofit, replacing all distribution pipes, but using the same system configuration.

Ventilation system

Ventilation systems supply air to the space and extract polluted air from it. Ventilation systems vary widely in terms of size and the functions they perform. The ventilation system is very important, because proper ventilation avoids water condensation and mold in your flat.

The design and specification of a building ventilation system has a big impact on energy use. Sometimes natural ventilation provides the best solution, while in other cases mechanical ventilation with heat recovery is needed. This depends from building type, use and occupancy. The specific system suiting your building has to be decided by ventilation experts during energy auditing and project design; in particular looking at the different options ranging from a fully centralised balanced ventilation systems or a decentralised hybrid ventilation system.

[1] U–value: a measure of the rate of heat transmission through a building part (as a wall or window) or a given thickness of a material. U-value, is the rate of transfer of heat through a structure (which can be a single material or a composite), divided by the difference in temperature across that structure. The units of measurement are W/m²K


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