diff --git a/smart-house/README.md b/smart-house/README.md
index ca4334f..8c9ff59 100644
--- a/smart-house/README.md
+++ b/smart-house/README.md
@@ -185,7 +185,7 @@
 
 Реализовать билдер для умного дома, позволяющий инициализировать объект умного дома в [таком стиле](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=5d0527e4684f726d54dc375829d983f4).
 
-- [ ] До добавления первой комнаты, билдер запрещает добавлять устройства. Это должно контролироваться компилятором.
+- [x] До добавления первой комнаты, билдер запрещает добавлять устройства. Это должно контролироваться компилятором.
 
 Реализовать компоновщик для построения отчёта об объектах умного дома в [таком стиле](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=c07dfc726e8ccbccdcc2d88a79d3f190).
 
diff --git a/smart-house/src/bin/room_builder.rs b/smart-house/src/bin/room_builder.rs
new file mode 100644
index 0000000..f59bb2b
--- /dev/null
+++ b/smart-house/src/bin/room_builder.rs
@@ -0,0 +1,11 @@
+use smart_house::{HouseBuilder, PowerSocket, PrintStatus, Thermometer};
+
+fn main() {
+    let house = HouseBuilder::new()
+        .add_room("Main")
+        .add_device("PSockA", PowerSocket::stub(12.0, false))
+        .add_room("Hall")
+        .add_device("ThermA", Thermometer::stub(18.5))
+        .build();
+    house.print_status();
+}
diff --git a/smart-house/src/builders.rs b/smart-house/src/builders.rs
index 71e797c..924a65b 100644
--- a/smart-house/src/builders.rs
+++ b/smart-house/src/builders.rs
@@ -1,51 +1,53 @@
 use crate::{Device, House, Room};
 use std::collections::HashMap;
 
-struct HouseBuilder {
+pub struct HouseBuilder {
     rooms: HashMap<String, Room>,
 }
 
 impl HouseBuilder {
-    fn new() -> Self {
-        Self {
-            rooms: HashMap::new()
-        }
+    pub fn new() -> Self {
+        Self { rooms: HashMap::new() }
     }
 
-    fn build(self) -> House {
-        House::new(self.rooms)
-    }
-
-    fn add_room(self, name: &str) -> RoomBuilder {
+    pub fn add_room(self, name: &str) -> RoomBuilder {
         RoomBuilder {
             parent: self,
             name: name.to_string(),
-            devices: HashMap::new()
+            devices: HashMap::new(),
         }
     }
+
+    pub fn build(self) -> House {
+        House::new(self.rooms)
+    }
 }
 
-struct RoomBuilder {
+impl Default for HouseBuilder {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+pub struct RoomBuilder {
     parent: HouseBuilder,
     name: String,
     devices: HashMap<String, Device>,
 }
 
 impl RoomBuilder {
-
-    fn add_device(mut self, name: &str, device: Device) -> Self {
-        self.devices.insert(name.to_string(), device);
+    pub fn add_device(mut self, name: &str, device: impl Into<Device>) -> Self {
+        self.devices.insert(name.to_string(), device.into());
         self
     }
 
-    fn add_room(mut self, name: &str) -> RoomBuilder {
+    pub fn add_room(mut self, name: &str) -> RoomBuilder {
         self.parent.rooms.insert(self.name, Room::new(self.devices));
         self.parent.add_room(name)
     }
 
-    fn build(mut self) -> House {
+    pub fn build(mut self) -> House {
         self.parent.rooms.insert(self.name, Room::new(self.devices));
         self.parent.build()
     }
-
 }
diff --git a/smart-house/src/device.rs b/smart-house/src/device.rs
index 2cb4ae3..16835b5 100644
--- a/smart-house/src/device.rs
+++ b/smart-house/src/device.rs
@@ -1,5 +1,6 @@
 use crate::PrintStatus;
 use std::fmt::Display;
+use std::io::Write;
 
 #[derive(Debug)]
 pub enum Device {
@@ -33,8 +34,8 @@ impl From<super::PowerSocket> for Device {
 }
 
 impl PrintStatus for Device {
-    fn print_status(&self) {
-        println!("{}", self.display());
+    fn print_status_into(&self, out: &mut impl Write) -> Result<(), std::io::Error> {
+        out.write_fmt(format_args!("{}", self.display()))
     }
 }
 
diff --git a/smart-house/src/house.rs b/smart-house/src/house.rs
index a619e7c..9741ad4 100644
--- a/smart-house/src/house.rs
+++ b/smart-house/src/house.rs
@@ -1,5 +1,6 @@
 use crate::{Device, Error, PrintStatus, Room};
 use std::collections::HashMap;
+use std::io::Write;
 
 #[derive(Debug)]
 pub struct House {
@@ -39,13 +40,15 @@ impl House {
 }
 
 impl PrintStatus for House {
-    fn print_status(&self) {
+    fn print_status_into(&self, out: &mut impl Write) -> Result<(), std::io::Error> {
         for (room_name, room) in self.rooms.iter() {
-            println!("{}:", room_name);
-            println!("{}", "-".repeat(32));
-            room.print_status();
+            out.write_fmt(format_args!("{}:", room_name))?;
+            out.write_fmt(format_args!("{}", "-".repeat(32)))?;
+            room.print_status_into(out)?;
+            out.write_fmt(format_args!("\n"))?;
             println!();
         }
+        Ok(())
     }
 }
 
diff --git a/smart-house/src/lib.rs b/smart-house/src/lib.rs
index 77b82da..35c3fd0 100644
--- a/smart-house/src/lib.rs
+++ b/smart-house/src/lib.rs
@@ -8,6 +8,7 @@ mod builders;
 mod print_status;
 mod thermometer;
 
+pub use builders::{HouseBuilder, RoomBuilder};
 pub use device::Device;
 pub use error::Error;
 pub use house::House;
diff --git a/smart-house/src/print_status.rs b/smart-house/src/print_status.rs
index 3f06159..92308dc 100644
--- a/smart-house/src/print_status.rs
+++ b/smart-house/src/print_status.rs
@@ -1,3 +1,9 @@
 pub trait PrintStatus {
-    fn print_status(&self);
+    fn print_status_into(&self, out: &mut impl std::io::Write) -> Result<(), std::io::Error>;
+
+    fn print_status(&self) {
+        if let Err(e) = self.print_status_into(&mut std::io::stdout()) {
+            eprintln!("Unexpected print error: {:?}", e);
+        }
+    }
 }
diff --git a/smart-house/src/room.rs b/smart-house/src/room.rs
index 38efac2..f54c5a9 100644
--- a/smart-house/src/room.rs
+++ b/smart-house/src/room.rs
@@ -1,5 +1,6 @@
 use crate::{Device, PrintStatus};
 use std::collections::HashMap;
+use std::io::Write;
 
 #[derive(Debug)]
 pub struct Room {
@@ -29,11 +30,12 @@ impl Room {
 }
 
 impl PrintStatus for Room {
-    fn print_status(&self) {
+    fn print_status_into(&self, out: &mut impl Write) -> Result<(), std::io::Error> {
         for (name, device) in self.devices.iter() {
-            print!("{} => ", name);
-            device.print_status();
+            out.write_fmt(format_args!("{} => ", name))?;
+            device.print_status_into(out)?;
         }
+        Ok(())
     }
 }