In connection with improvement of public welfare, coming to the fore are requirements enabling comfortable living, which primarily depends on conditions of indoor air environment. This article provides arguments to suggest that, during reconstruction and overhaul of residential buildings, natural ventilation systems, failing to provide the required air exchange, need to be replaced with hybrid ventilation systems, allowing to maintain stable ventilation in existing multi-storey buildings throughout the year and involving minor capital and operating costs. Based on the example of a typical nine-storey residential building, two variations of hybrid ventilation have been developed: containing an ejector and roof fans, with economic feasibility of using both determined.

Keywords: microclimate quality, air exchange, natural ventilation, hybrid ventilation, an ejector, a roof fan, economic feasibility

The article considers possible ways to increase energy efficiency of ventilation systems in residential buildings via replacing natural ventilation by means of mechanical systems with heat recovery of exhaust air. A feasibility study has been completed covering the application of the central zone and single apartment mechanical air-handling ventilation units with respect to social and planning solutions approved in the course of renovation of residential buildings under Volgograd specifics, which showed that the single apartment systems are not economically viable for use with smaller apartments in terms of number of rooms and overall area (economy housing).

Keywords: energy saving, natural ventilation, the mechanical central zone ventilation system, the single apartment ventilation system, recovery, a planning solution for a building, economic feasibility

Currently, the quality of the microclimate, which ensures comfortable living of people comes to the fore in comparison with energy saving. One consequence of the desire for energy conservation has been increased sealing of window openings, which has disrupted the natural ventilation system and worsened air quality in residential buildings, which is particularly dangerous in the face of increased coronavirus infection. The article justifies the need to replace the reconstruction and overhaul of residential buildings of natural ventilation systems, which do not provide the necessary air exchange in residential buildings with airtight windows, to autonomous mechanical ventilation exhaust systems with the recovery of the heat of the exhaust ventilation air in the conditions of Volgograd..

Keywords: energy conservation, energy efficiency, microclimate quality, natural ventilation, mechanical ventilation with recovery

The article describes an integrated approach to the replacement of heating appliances in residential buildings in the event of major repairs or mechanical wear of these devices. The conditions of use of different types of modern heating appliances in existing heating systems have been analyzed. Based on experimental data, an analysis has been conducted for the operation of an aluminium radiator in a single-pipe up-feed heating system with respect to various radiator connection options to the riser. Recommendations have been provided on usage of modern types of heating appliances in residential buildings.

Keywords: the heater, thermal comfort, the response time, a single-pipe heating system, the connection diagram of the heater to the riser.

This paper describes the main directions of development of low-power boilers and the analysis of existing methods of heat transfer enhancement in these boilers. Shows generalising dependence reliably reflecting the impact of intermediate emitters on heat transfer in convection surfaces of water-tube boilers. The use of intermediate emitters can improve the energy efficiency of low-power boilers and reduce their negative impact on the environment

Keywords: low power boilers, energy, convective heating surfaces, intensification of radiant heat transfer, intermediate emitters