What it costs: mechanical ventilation | Features

Specification options	Capital cost £/item	Net present value for 60 years	Service life years
Ventilation components
Low velocity air handling unit with heating coils, filters and fans, internal location 2m³ at 350Pa, including louvres, dampers, ductwork to louvres, attenuators	9,000	35,950	15-20
Galvanised steel ductwork to DW144 tested to BS EN 12237, supply and extract ducts, dampers and attenuators.	7,500	26,110	30-35
Fans
Axial flow fan, 500mm diameter 2m3/s duty at 500Pa, 415V, 3 phase with anti-vibration mountings; 2 fans	2,000	15,840	20-30
Centrifugal duct mounted in-line fan; duty: 3m³ at 500 Pa Impellor backward curved. 415V, 3 phase; 2 fans	4,000	19,980	20-30
Table notes: Costs modelled on a nominal office building of five storeys with a gross internal area of 2,000m². Costs include maintenance, cleaning, testing, filter replacement, minor repairs, component replacement and energy, as applicable. A discount rate of 3.5% is used to calculate net present values. A cost analysis based on project specific information is essential for a realistic best value appraisal. Building Life Plan provides latent defect warranties for buildings www.blpinsurance.com. For durability information contact: peter.mayer@blpinsurance.com or telephone 020 7204 2450